Contents and Abstracts: 2004-2009:

2009, Issue LV (LIX): Fasc. 1, Fasc. 2, Fasc. 3,Fasc. 4

2008, Issue LIV (LVIII): Fasc. 1, Fasc. 2, Fasc. 3,Fasc. 4

2007, Issue LIII (LVII): Fasc. 1-2, Fasc. 3-4

2006, Issue LII (LVI): Fasc. 1-2, Fasc. 3-4

2005, Issue LI (LV): Fasc. 1-2, Fasc. 3-4

2004, Issue L (LIV): Fasc. 1-2, Fasc. 3-4

Open Acces Journal: 2020-2016
Contents and Abstracts: 2010-2015

2009, Issue LV (LIX), Fasc. 1

Voltammetric Study On The Cd2+ - Pb2+ - Cu2+ Ternary System

DOINA BEJAN, AL. DUCA

pages 9 - 19
Abstract
The present paper is aimed to report the qualitative and quantitative study on the voltammetric behaviour of the Cd2+ - Pb2+ - Cu2+ ternary system in slightly acid (10-1 mol/L, acetate buffer, pH = 4.5) solutions of (2 - 5) 10-6 mol/L concentrations, on the carbon paste electrode (CPE) and CPE electrodes modified with NAFION (NAFION coated carbon paste electrodes (NC-CPE), and NAFION entrapped carbon paste electrodes (NE-CPE)). The influence of the electrode nature, the pre-concentration and ion-exchange pre-concentration time, the potential scanning rate, on the ternary system voltammetric behaviour were followed. The intensity of the anodic current, as a signal of analytical interest, increases rather proportionally with the increasing of ions concentration and concentration time, and depends on the electrode nature. The method can be applied for identifying and estimating the low concentrations of Cd2+, Pb2+ and Cu2+ ions in complex environmental and biologicalsystems.
Keywords: Cd2+-Pb2+-Cu2+ ternary system, ion-exchange voltammetry, NAFION-ionomer, CPE, NAFION-CPEs

Biosorption Of Heavy Metals From The Environment Using Yeasts As Biosorbents

RALUCA MARIA HLIHOR, MARIA GAVRILESCU

pages 21 - 37
Abstract
Pollution with heavy metal is one of the most important environmental problems today, since various industries and human activities produce and discharge wastes containing different heavy metals into the environment. Thus, metal as a kind of resource is becoming shortage, it also brings about serious environmental pollution, threatening human and ecosystem health. Biosorption is considered as a feasible alternative for removing heavy metals from the environment, which utilizes various natural materials of biological origin, including bacteria, fungi, yeast, algae as sorbents. The first major challenge for the biosorption field was to select the most promising types of biomass from an extremely large pool of readily available and inexpensive biomaterials. In the field of biosorption, yeasts have proved to be efficient sorbents and many researches are reported and reviewed findings on the removal of heavy metal ions. Due to their unicellular nature and high growth rate, the studies have clearly demonstrated that yeasts can be used for trace enrichment of metal ions in aquatic environments. The paper analyses some theoretical and practical aspects on the topic of biosorption and specifies the main features involved in the biosorption of heavy metals when yeasts are used as sorbent, also providing some practical examples.
Keywords: environmental pollution, biosorption, sorbents, heavy metal removal, yeast

A New Coordination Compound Of Cd(II) With Ligand Derived From N,N-bis (Salicylidene) - Methylenediamine

DOINA SIBIESCU, IRINA SPĂTĂRESCU, IOAN ROŞCA, MIHAELA VIZITIU

pages 39 - 47
Abstract
A new coordination compound of cadmium (II) with ligand derived from N,N-bis (salicylidene) – methylenediamine (Salmen) of molar ratio 1:1 was synthesised and studied. The studies were made using the methods: chemical analysis, IR absorption spectroscopy, thermogravimetry and X-ray diffraction. The new compound presented a crystalline structure in triclinic lattice with central atom Cd(II) tetracoordinated in tetrahedrical structures. The obtaining reaction of the new compound is important for gravimetric determination of Cd(II) with an error of ±0,25%.
Keywords: Cadmium(II), N,N-bis (salicylidene) - methylenediamine (Salmen), precipitating reagent, gravimetric determination.

Role Of Microorganisms In Organic Compounds Degradation

LAURA CARMEN APOSTOL, MARIA GAVRILESCU

pages 49 - 64
Abstract
In recent years the ability of microorganisms to metabolize organic compounds has received much attention for environmental protection purposes due to the environmental persistence and toxicity of these pollutants. The degradation of organic compounds can take place with in the presence of bacteria, fungi, yeast and other organisms under aerobic and anaerobic conditions and depends on the biodegradability of organic compounds. This paper describes some biodegradation processes of organic compounds originating from the activity of microorganisms in the environment. The processes are considered in the context of using these processes in natural and anthropic ways, which are introduced to technological practice in order to clean up particular environmental compartments.
Keywords: organic compounds, bacteria, fungi, yeasts, bioreactors.

A Regression Analysis Study Of Gas Drying By Adsorption On Composite Materials

MARIUS SEBASTIAN SECULA, RODICA DIACONESCU, STELIAN PETRESCU

pages 65 - 77
Abstract
The purpose of this paper lies in the study by regression analysis of gas drying by adsorption in fixed bed of composite materials. The experimental investigations were carried out at two values of relative humidity and three values of air flow rate respectively. The evolution in time of some adsorption parameters, such as adsorption rate, water concentration in the bed, water vapour concentration in air at the exit from the fixed bed, drying degree and rate respectively is studied by regression analysis. Based on these adsorption parameters, two composite adsorbent materials having porous matrices were compared.
Keywords: gas-drying, adsorption, mathematical modelling, mass transfer, Silica gel.

2009, Issue LV (LIX), Fasc. 2

Reduction of Energy Consumption for Nickel Electroplating Process

FLORIN BANDRABUR, LILIANA LAZĂR

pages 9 - 19
Abstract
In this paper, an analysis of the influence of the parameters upon the energy consumption needed for nickel electroplating process onto steel supports is performed. Reduced energy consumption leads to a great energy yield, diminishing in the same time, the cost of the final product, fact that satisfies the financial calculus of any economic agent. The practical energy consumption is directly proportional with the terminal voltage of the electrolyser. This depends on the electrolyte composition and the operating parameter and is significantly influenced by the voltage drop through the electrolyte. For an electro-chemical reactor that functions at a certain temperature, the proper selection of the distance between the electrodes, in order to decrease the voltage drop through the electrolyte and, consequently, the energy consumption, is essential.
Keywords: nickel electroplating, energy yield, energy consumption.

Kinetic and Thermodynamic Aspects of the Cationic Dye Removal from Aqueous Solutions onto Fibrous Materials

DANIELA ŞUTEU, DOINA BÎLBĂ, TEODOR MĂLUŢAN

pages 21 - 30
Abstract
In order to find new materials with sorptive properties, the alkaline hydrolyzed polyacrylonitrile fibres (Melana, Romania) (HPAN fibres) were tested in removal of some textile cationic dyes from aqueous solutions. Kinetic and thermodynamic studies were carried out to establish the favorable conditions for removal of dyes and to understand the sorption mechanism. The kinetics of the sorption of Methylene Blue and Crystal Violet dyes was analyzed using the pseudo-first order and pseudo-second order kinetic models. The kinetic data fitted well to the pseudo-second order kinetics, indicating the chemisorption of dyes onto fibrous sorbent. The thermodynamic parameters ΔG, ΔH and ΔS were determined; the obtained values show that the sorption of the studied dyes on HPAN fibres is a spontaneous, endothermic and entropy-driven process. The sorption mechanism of the cationic dyes onto hydrolyzed fibres was confirmed by FTIR spectroscopy. The results of this study evidenced that the hydrolyzed polyacrilonitrile fibres may be an inexpensive and efficient sorbent for textile dyes removal from aqueous media
Keywords: hydrolyzed polyacrylonitrile fibres, cationic dyes, sorption, kinetics, thermodynamic study, FT-IR analysis.

Study of a New Complex of Cu(II), with 1-(3,5 Diiodo, 4 Methyl, 2 Hydroxy, Phenyl)- 2 Phenylsulfanyl Ethanone Ligand

IRINA SPĂTĂRESCU, DOINA SIBIESCU, IOAN ROŞCA , MARIUS SEBASTIAN SECULA

pages 31 - 39
Abstract
In this paper are presented the synthesis and study of a new complex obtained from the reaction of Cu(II) with 1-(3,5 diiodo, 4 methyl, 2 hydroxy, phenyl)-2 phenylsulfanyl ethanone. The novel complex, Cu(C15H11O2SI2)2, crystallizes in orthorhombic systems having as central atom Cu(II) tetracoordinated with oxygen atoms from the groups >C=O and •OH (phenolic). The obtaining reactions of this complex can be used in the gravimetric determination of Cu(II), with an error of ± 0.21%.
Keywords: Copper(II), precipitating reagent, gravimetric determination..

Bioreactors of “Basket” Type with Immobilized Biocatalysts

ROXANA BALTARU, ANCA-IRINA GALACTION, DAN CAŞCAVAL

pages 41 - 53
Abstract
The spectacular applications of the immobilized biocatalysts determined the design and construction of some proper bioreactors, specific or derived from the “classical” ones. Among them, the bioreactors with immobilized biocatalysts are some of the most studied and applied bioreactors. The biocatalyst could be disposed around the stirrer in a fixed bed with cylindrical geometry. This type of bioreactor is known as “basket bioreactor”. In this context, the aim of the paper is to briefly review the recent literature on the main types of the “basket” bioreactors with immobilized biocatalysts, from the viewpoint of their construction and applications, by analyzing their advantages/disadvantages comparatively to the other types of bioreactors
Keywords: bioreactor, immobilized cells, biocatalyst, fixed bed, basket bioreactors

Studies Regarding the Influence of Separation Method on Physico-Chemical Properties of Microfibrillated Cellulose Structures

PETRONELA NECHITA, TEODOR MĂLUŢAN, DANIELA MANEA

pages 55 - 65
Abstract
In the conditions of shortage of resources reserves and their use in the open cycle, it is necessary to identify the alternatives of raw materials. In this context, the cellulose micro fibrillated structures extracted from plant tissues is a new way for processing and using of annual plants and wood products. Due to the economical and environmental advantages that are emphasized, these structural elements facilitate the obtaining of composite materials with high strength and durability that can be used in the high industrial fields, such as: electronics, communications, buildings, medicine, etc. In this paper are analyzed the results obtained after chemical (acid and alkaline extraction) and chemical- mechanical treatments (wet refining in the laboratory Hollander and colloidal mill combined with acid hydrolysis) aiming to obtain the cellulose micro-structural elements, using as raw material bleached softwood pulp.
Keywords: Fibres, Microfibrilar structures, Composites, Chemical preparation, Mechanical processing, Electronic microscopy, Optical microscopy.

Life Cycle Impact Assessment of Pesticides: Current Issues and Perspectives

LAURA CARMEN APOSTOL, RALUCA MARIA HLIHOR, CAMELIA SMARANDA, VASILE LUCIAN PAVEL, BRINDUSA MIHAELA ROBU, FLORENTINA ANCA CĂLIMAN , MARIA GAVRILESCU

pages 67 - 83
Abstract
The paper analyses some aspects concerning the Life Cycle Assessment as a tool for assessing the comprehensive environmental impacts of products, processes and activities within environmental management and decision making process. A special emphasis has been paid to pesticides impacts, risks and toxicity for environment and human health. Pesticides are biologically active substances that are directly released to the environment during the use phase of their life cycle. Pesticides are widely used and play an important role in the production of vital goods such as food, feedstuffs and others, so that pesticide life cycle analysis (PLCA) as a new procedure to discover concrete deficiencies in the production, international trade, national distribution, local application and storage. PLCA can be used for accounting the effects of application and lack of application of pesticides.
Keywords: environment, human health, impact, inventory analysis, modelling, pesticides, risk.

Vegetal Fibers in Composite Materials - Advantages and Limitations

DAN GAVRILESCU, BOGDAN MARIAN TOFĂNICĂ, ADRIAN CĂTĂLIN PUIŢEL, PUIU PETREA

pages 85 - 104
Abstract
Transition to a more sustainable economy and the consequences of the Kyoto protocol on global climate changes determine a shift of feedstock for energy and chemical industries from fossil fuels and petrochemicals to renewable resources. The use of vegetal fibers as major source of renewable resources represents a valuable alternative both from economical and environmental points of view. Traditionally, vegetal fibers are widely used in textile industry, paper manufacture, and packaging. Due to their specific properties, vegetal fibers are gained increased attention in obtaining composite materials. This paper reviews the advantages and limitations of vegetal fibers that can be potentially used as reinforcements in composite materials. The properties of wood and annual plant fibers are briefly discussed. Some considerations regarding environmental impact of using vegetal fibers in composites are underlined.
Keywords: vegetal fibers, nonwoods, composites, renewable resources, environment.

2009, Issue LV (LIX), Fasc. 3

Lead(II) Extraction in Aqueous PEG(1550) – (NH4)2SO4 Two-Phase Systems Using Iodide Ions As Extracting Agent

LAURA BULGARIU, DUMITRU BULGARIU

pages 9 - 18
Abstract
The extraction behaviour of lead(II) ions was studied in aqueous polyethylene glycol (PEG) – (NH4)2SO4 two-phase systems, in absence and in presence of iodide extractants, as a function of several experimental parameters. The aqueous two-phase system, obtained by mixing equal volumes of phase-forming components (PEG and (NH4)2SO4) solutions, is composed by two immiscible phases and can be used for the extraction studies. In absence of suitable extractant, the lead(II) extraction is insignificant, and the variation of salt stock solution pH does not change too much the extraction efficiency. The addition of iodide ions determined a quantitative partition of lead(II) into PEG-rich phase. The lead(II) extraction efficiency depends by the acidity of salt stock solution and by the concentration of iodide added in extraction system.
Keywords: lead(II), iodide extractant, extraction, aqueous two-phase system.

Overview on Chromium Occurrence in the Environment and Its Remediation

RALUCA MARIA HLIHOR, LAURA CARMEN APOSTOL, VASILE LUCIAN PAVEL, CAMELIA SMARANDA, BRÎNDUŞA MIHAELA ROBU, FLORENTINA ANCA CĂLIMAN, MARIA GAVRILESCU

pages 19 - 35
Abstract
This paper first reviews the different forms of Cr present in the environment as a function of environmental conditions. There are also discussed the transport and fate of Cr(VI) as well as other forms of Cr in the environment, most notably Cr(III). These forms or species of Cr are inevitably linked by many environmental transport and fate processes. The form of the Cr determines toxicity, mobility, and treatment strategy applicability. Subsequently, a summary of common chemical processes (reduction/oxidation, adsorption/desorption and precipitation/dissolution), biological processes (reduction/oxidation, biosorption) and physical processes utilized in remediation technologies were presented. Finally, treatment technologies will be organized into three different categories: toxicity reduction methods, removal treatments, and containment technologies and discussed.
Keywords: contamination, environment, heavy metals, human health, modelling, oxidation state, persistence, remediation, speciation.

Synthesis And Thermal Behavior of Some Mesogenic Compounds Containing Azo Linkage

ELENA-RALUCA CIOANCĂ, CĂTĂLINA CIOBANU, GABRIELA LISA, DAN SCUTARU

pages 37 - 48
Abstract
The synthesis and thermal characterization of some mesogenic groups containing azo likage are reported. Compounds were prepared by Williamson alkylation reaction or esterification of 4’-hydroxy-4-formylazobenzene with linear alkyl bromides with 6 - 10 and 18 carbon atoms or carboxylic acids containing 5 - 10 and 18 carbon atoms. The thermal stability of these compounds was established by using thermogravimetric analysis. The reported compound do not present liquid crystalline properties, but they may be used in the synthesis of new classes of Schiff bases by reaction with specific diamino cores for formation of bent core liquid crystals.
Keywords: thermal behavior, mesogenic groups, azo derivatives

Optimization Of W/O Emulsions Based on Polysaccharides

MIHAELA IANCU, MARCEL POPA, THIERRY HAMAIDE

pages 49 - 56
Abstract
This paper tries to optimize the preparation of stable w/o emulsions based on starch and 2-hydroxyethylcellulose as gelling agents for the aqueous phase. The emulsification could be achieved at 70◦C in spite of the high viscosity of the aqueous phase; the internal phase gelled upon cooling to room temperature. The high viscosity of the aqueous phase limited the possible concentration range of polysaccharide in the aqueous phase for a correct emulsification. The presence of polysaccharides made the surfactant demand larger for both the emulsification and the stabilization of the w/o emulsions. Certain formulation variables, such as polysaccharide nature and concentration, phase ratio, surfactant concentration and mixing regimen, were investigated in order to obtain stable w/o emulsions
Keywords: starch and 2-hydroxyethylcellulose, water/oil emulsion

1,4-Disubstituted Thiosemicarbazides With Potential Tuberculostatic Action

MIHAELA MOISE, VALERIU ŞUNEL, LENUŢA PROFIRE, MARCEL POPA, JACQUES DESBRIERES, CRISTIAN PEPTU

pages 57 - 64
Abstract
New thiosemicarbazides derived from N-(p-nitrobenzoyl)-phenylalanine with potential tuberculostatic action were obtained through the reaction of the N-(p-nitrobenzoyl)-phenylalanine hydrazide with aromatic isothiocyanates. The chemical structure was confirmed by elemental and spectral (FT-IR, 1H-NMR) analysis. The tests performed on the toxicity and tuberculostatic activity recommends such compounds as a possible clinical alternative to the drugs now in use.
Keywords: thiosemicarbazides, tuberculostatic inhibitors, hydrazides, phenylalanine derivatives.

Synthesis Of Cephalosporin Glutamic Acid Derivative: Its Immobilization On Microbial Polysaccharides

DANIELA DUMITRAS, MARCEL POPA, VALERIU SUNEL

pages 65 - 87
Abstract
This paper studies the synthesis and the dicyclohexyl carbodiimide activated immobilization reaction through ester-type covalent bonds of an oxazolone derived from N-(m-nitrobenzoyl)-L-glutamic acid, ring opened with 7- aminodesacetoxicephalosporanic acid (A7ADC) on polysaccharides (gellan and xanthan). The maximal efficiency of coupling reaction was obtained for the active principle – gellan system. For both systems was realised an experimental program varying the following parameters: molar ratios DCCI/medicament and medicament/support as well as the reaction time. To achieve a maximum content of biologically active product in the immobilization compounds, the highest values of the parameters are used. The kinetics of the drug release process are studied in alkaline hydrolyse conditions.
Keywords: cephalosporin, aminoacid derivative, gellan, xanthan, drug delivery.

New Hydrazones of 5-nitroindazol-1-Yl– Acethydrazide With Pharmacological Potential

CORINA CHEPTEA , VALERIU ŞUNEL, LENUŢA PROFIRE, MARCEL POPA, CĂTĂLINA LIONTE

pages 89 - 95
Abstract
The actual concern for the preparation of new substances with drug action involved – among others – the synthesis of hydrazones derived from 5-nitroindazol-1-yl-acethydrazide. In this point of view, the ethyl ester of the 5-nitroindazol-1- yl acetic acid was synthesized, then subjected to the reaction with hydrazine hydrate, when 5-nitroindazol-1yl- acethydrazide was obtained. Further on, its condensation with various aromatic aldehydes gave a new series of N-acyl- hydrazones. The chemical structure of the new synthesized compounds was confirmed through elemental and spectral (FT-IR, 1H-NMR) analysis. Toxicological tests were also performed and the obtained results recommend hydrazones as potential therapeutical candidates.
Keywords: hydrazones, hydrazidones, antimicrobial activity, anti-tuberculosis activity

Studies Regarding the Influence of Reaction Conditions on the Synthesis of Silver Nanoparticles

GABRIELA APOSTOLESCU, GABRIELA CARJA, NICOLAE APOSTOLESCU, MOHAMED CHIBAN, ELENA HUSANU

pages 97 - 107
Abstract
The paper explores the influence of process parameters for synthesis of silver nanoparticles. Obtained nanoparticles were characterized by UV-Vis spectroscopy and transmission electron microscopy. Average particle diameter obtained ranged from 50 to 10 nm and is depending on the used reducing agent nature, the type of surfactant and its concentration.
Keywords: silver nanoparticles, PVA and APA surfactant.

2009, Issue LV (LIX), Fasc. 4

Convective Drying Kinetics of Porous Granules Support Based Catalytic –Al2O3

LILIANA LAZĂR, MARCEL VRÂNCEANU, ION BALASANIAN, STELIAN PETRESCU

pages 11 - 22
Abstract
In this paper, the researches regarding the kinetics of the convective drying of the porous granules based on –Al2O3, manufactured by extruding and used as support for synthesis of the catalyst through impregnation without interaction are presented. Within this technology, the drying process that allows the removal of water from pores and crystallization of the active component exhibits a determinant role for achieving good catalytic properties. The drying curves were gravimetrically determined at the atmospheric pressure, in the temperature range of 313 and 343 K, at different velocities of the drying agent (0.67 – 2.52 m/s). The analysis of the experimental data shows that the process is favourably influenced by the increase of the process temperature and the increase of the drying agent velocity as well. Using the experimental data, the drying rate was calculated and its dependence of the humidity of the material was plotted. Kinetic equations for the stages of the drying process have been proposed and the kinetic constants were determined from these models.
Keywords: catalytic support, alumina, convective drying, kinetic analysis.

CD and FT-IR Study of Some Adducts of Albumin with Toxic Dinitrophenyl Derivatives

GABI DROCHIOIU, ADRIANA ADOCHIŢEI, LAURA HĂBĂSESCU, GHEORGHIŢĂ ZBANCIOC, AUREL PUI, ROBERT GRĂDINARU, ELENA RUSU

pages 23 - 28
Abstract
Conformational alterations of biomolecules are very important in biological systems, forming part of the chain of interactions leading to signal transduction. The CD spectra in the far-UV region show that albumin has a slightly altered conformation if dinitrophenyl derivatives are present in protein solution. The CD signal becomes more complex in the positive region around 190-197 nm; the strong negative peak at 227 nm changed both the position and the intensity upon dinitrophenol binding. Although the spectrum is slightly different, probably because of the interaction between the peptide/protein and DNP, no evidence for an ordered structure such as helix or β-sheets can be found. FT-IR measurements also confirmed conformational changes on binding dinitrophenols to albumin and other proteins. Our results suggest that albumin could be a protective agent against pesticide dinitrophenols.
Keywords: peptide synthesis, metal-affinity, peptide conformation, circular dichroism.

Sawdust as Biosorbent for Removal of Dyes from Wastewaters. Equilibrium Study

DANIELA ŞUTEU, CARMEN ZAHARIA

pages 29 - 37
Abstract
The sawdust, the waste from the wood industry was study as alternative low cost biosorbent in removal of reactive dye Orange 16 from aqueous solutions. In this paper we study the equilibrium process to determine the quantitative characteristic parameters. In this context Freundlich, Langmuir, Dubinin-Radushkevich and Tempkin isotherm models were investigated at three temperatures. According to Langmuir isotherm, the maximum sorption capacity was estimated as 8.554 mg g-1 (20ºC). Dubinin-Radushkevich equation was used to determine the energy of sorption and to estimate the nature of the sorption process. The sorption energy determined in the Dubinin-Radushkevich equation (9.45 kJ mol-1 at 20ºC) revealed an ion exchange mechanism for the reactive dye sorption onto sawdust.
Keywords: sorption, reactive dye, sawdust wastes, sorption isotherms.

Cellulose Acetate Membrane: Preparation and Characterisation

GABRIELA CIOBANU, DORINA IGNAT, GABRIELA CÂRJĂ, CONSTANTIN LUCA

pages 39 - 46
Abstract
Cellulose acetate membranes are used extensively in reverse osmosis for the removal of salt from water. In this study asymmetric membranes were fabricated from a ternary system consisting of cellulose acetate, acetone and formamide or water using a phase inversion process. These membranes were asymmetric-hydrophilic type with thickness less than 200 tm.
Keywords: cellulose acetate membranes, phase inversion process.

Environmental Impact Assessment for an Industrial Unit of Bricks Production

CARMEN ZAHARIA

pages 47 - 57
Abstract
The environmental impact (EIA) for the studied industrial unit of bricks production is assessed using both alternative method of global pollution index (I*PG) and the well-known method of global pollution index (IPG). The evaluated environment components are considered to be: air, water resources (i.e. ground water and final industrial effluent) and soil. The experimental results correspond to the situation of ‘environment modified by industrial/economic activities into admissible limits’ (I*GP = 1.53, and IGP= 1.85). In this context, the industrial company was implementing monitoring actions in order to prevent/control environment pollution.
Keywords: bricks production, environment pollution, environmental impact assessment (EIA), global pollution index

Study Regarding the Modification of Some Lignins from Annual Plant Through Epoxydation

ADINA-MIRELA CĂPRARU, VALENTIN I. POPA, GABRIELA LISĂ, TEODOR MĂLUŢAN

pages 59 - 68
Abstract
In this paper are presented the results obtained by modification of annual plant lignins through epoxydation: L1 (lignin of wheat straw), L2 (lignin of grass), and commercial products (Pb1000 Pb2000, Pb3000), offered by GRANIT company. Reaction with epichlorohydrin was performed in basic catalysis, aiming at increase functionality. The resulting products were characterized in terms of functionality (content of epoxy groups) and by FTIR and UV-VIS spectroscopy. It was also performed a study of lignin derivatives by thermogravimetry which allowed to establish a correlation between modification degree and thermal stability.
Keywords: lignin, epoxydation, FTIR, UV-VIS, thermal analysis.

Chestnuts (Castanea Sativa) Extracts − A Potential Plant Growth Regulator

ALINA STÎNGU, IRINA VOLF, VALENTIN I. POPA

pages 69 - 77
Abstract
The valorization of waste products represents an increasing challenge of economically sustainable and environmentally friendly industrial processes. Chestnuts could be considered an important raw material in those regions where these trees are growing, not only for the fruit, but also for the wood. The aim of this paper was to investigate the potential of chestnuts (Castanea sativa) shell aqueous extract as plant growth regulator. Growth regulator potential of this extract was evaluated in rape and oat seeds germination test by biometric measurements of seedling plantlet and quantitative determination of fresh biomass. Germination capacity, chlorophyll - and total chlorophyll content were estimated for both rape and oat plantlets.
Keywords: chestnuts shell, aqueous extract, rape, oat, chlorophyll.

Biomechanical Factors in Living Tissues Growth

OCTAVIAN CIOBANU, GABRIELA CIOBANU

pages 79 - 88
Abstract
Biomechanical factors influence the processes of tissue growth, development, degeneration, and repair. Regenerative strategies to restore damaged tissues in vivo and to create living tissue replacements in vitro have begun to exploit advances in understanding of how cells and tissues adapt to their mechanical environment. All tissues from the body are living under pressure, due to gravity, due to blood pressure and due to other organs pressure. If a tissue is removed from the body, the obtained unloaded state is not naturally stress free. This stress state within an unloaded body is called residual stress. The residual stress may help the tissue to optimize its functions. The paper reviews the present state of art in residual stress evaluation in living tissues using several examples. Biomechanical factors are a keystone to the successful application of therapies based on principles of tissue engineering in biomedical researches.
Keywords: living tissue, biomechanical factors, residual stress.

Conformational Changes of Peptides on Binding Metals: CD & FT-IR Studies

MANUELA MURARIU, ECATERINA STELA DRĂGAN, ADRIANA ADOCHIŢEI, LAURA HĂBĂŞESCU, GHEORGHIŢĂ ZBANCIOC, AUREL PUI, GABI DROCHIOIU

pages 89 - 94
Abstract
Two 19-residues alanine-rich peptides containing histidine residues in various positions, namely AAAAHAAAAHAAAAHAAAA (P1), and AAAHAAAHAAAHAAAAAAA (P2) have been synthesized by Fmoc strategy and treated with heavy metal ions, such as Ag+, Hg2+, Pb2+, Ni2+, Cu2+, Zn2+, Fe2+, etc. Both peptides and metal ion-complexes have been characterized by Fourier transform infrared (FT-IR) spectroscopy, electrospray ion trap mass spectrometry (ESI-MS) and circular dichroism (CD). CD and FT-IR spectra showed that P1 and P2 have completely different conformations and that only P1 is able to bind easily metal ions to form complexes with an altered conformation. Because of rigid conformation as revealed by CD, P2 is less able to accommodate metal ions. Consequently, P2-metal ion spectra proved to be similar to those of pure P2.
Keywords: peptide synthesis, metal-affinity, peptide conformation, circular dichroism.

Study Regarding the Influence of Asclepias Syriaca Aqueous Extracts in the Development of a Strain of Yeast (Rhodotorula SPP.)

ANCA-ROXANA HAINAL, IRINA VOLF, VALENTIN I. POPA

pages 95 - 101
Abstract
This paper presents the results obtained in the study of Rhodotorula spp. yeast cultivation in a culture medium containing aqueous extract of Asclepias syriaca at different dry substance concentration levels. The fermentation process was followed through quantification of wet and dry biomass. After the wet biomass was recovered, residual sugar and polyphenol concentration (by Folin-Ciocâlteu method) was analyzed in the culture medium. Also the pH was determined every 24 hours along the nine days period of the experiment.
Keywords: Asclepias syriaca, Rhodotorula spp., biomass, residual sugar, polyphenols pH, Folin-Ciocâlteu method.

Optimization Study of Orange 16 Dye Sorption Onto Sawdust Wastes

CARMEN ZAHARIA, DANIELA ŞUTEU

pages 103 - 113
Abstract
The application of sawdust wastes as adsorptive materials into a textile wastewater treatment based on sorption technology followed by solid/liquid separation using mechanical operations such as sedimentation and filtration was indicated to be studied into last years taking into account the recycling requirements of treated wastewater/final effluent or “zero” effluent discharge into aquatic environment. All kinetic experiments were performed on a laboratory scale set- up in order to establish the optimal operational conditions (e.g., sawdust quantity, pH, sorption time, temperature) for high removal efficiencies of Orange 16 dye. Variables concerning the sawdust quantity (0.1-0.3 g per 25 mL), pH (1-4), and sorption time (5-160 min) are considered in order to appreciate the treatment efficiency. An empirical model was proposed by a third order compositive rotatable design, considering these variables as independent ones, while dye removal was chosen as optimization criteria. The local optimum values correspond to a sawdust quantity of 0.15 g per 25 mL dye solution, a pH of 1, and a sorption time of 50 min for a maximum dye removal of 57.3 8%.
Keywords: optimization, experimental design, sorption, Orange 16 dye.

Study of Radish (Raphanus Sativus L.) Response to Elevated Level of Cadmium and Copper Ions

ALINA STÎNGU, IRINA VOLF, VALENTIN I. POPA

pages 115 - 124
Abstract
Human activities release pollutants in the environment; heavy metals, in particular, originated from industrial emissions, mining activity, disposal of wastes and fertilizer and pesticide use. Phytoextraction can provide an effective in situ technique for removing heavy metals from polluted soils. The experiment reported in this paper was undertaken to study the basic potential of phytoextraction of Raphanus sativus (radish) grown in a elevated levels of copper and cadmium contaminated sandy soil using a vegetative pots-experiment. Biometric measurements of root, steam, leaf length and quantitative determination of fresh mass were carried out to point out the morphological changes induced by the presence of heavy metals in the growth medium. The heavy metal content and bioaccumulation coefficient of radish plant were also determined and the degree of recovery for each metal was calculated. The obtained data indicated that radish plants are moderately tolerant to heavy metals.
Keywords: radish, heavy metals, bioaccumulation coefficient, degree of recovery.

General Aspects of Life Cycle Assessment for Paper and Board Products

ALINA IOSIP, ELENA BOBU

pages 125 - 138
Abstract
The paper presents the four basic stages of Life Cycle Assessment (LCA) as a tool to evaluate the environmental impact of processes and products and some aspects concerning the application of LCA in pulp and paper industry. A special emphasis was put on the types of waste generated in the pulp and paper manufacture and ecological and human health effects, which define impact categories that could be assessed by LCA studies.
Keywords: life cycle assessment (LCA), environmental impact, waste management, pulp, paper.

The Alcoholic Fermentation Study of the Saccharose

NECULAI CĂTĂLIN LUNGU, MARIA ALEXANDROAEI

pages 139 - 148
Abstract
The aim of the present work is to evidence what are the technological- economic parameters which characterize the alcoholic fermentation of the saccharose in the presence of the Saccharomyces cerevisiae yeast to different mean temperatures. The study was carried out using a saccharose substrate with/no admixture of nutritive substances, in a glass bioreactor. The experimental results conducted us to the conclusion that the introduction of the nutritive substances containing N,P,S,K and Mg elements, along with the growing factors from the Saccharomyces cerevisiae yeast influence the enhancement of the cellular metabolic processes and the decreasing of the fermentation total time.
Keywords: alcoholic fermentation, technological-economic parameters, saccharose.

UV Laser Applicability in Study of Accelarated Ageing of Cellulosic Supports

NARCISA VRÎNCEANU, DIANA COMAN, ION SANDU, AURELIA GRIGORIU, VIORICA VASILACHE

pages 149 - 155
Abstract
The aim of this research was to comparatively determine the immediate effects of irradiation treatment, of two types of lasers (excimer pulsed laser and Nd: YAG pulsed laser), on paper. The long-term impact of UV laser treatments performed onto the stability of cellulose, by means of accelerated aging method, has been evaluated as well. UV laser treatments disrupt long-term stability of paper (highlighted by degree of polymerization –DP changes in GP and brightness of the substrate). Accelerated aging tests have shown that the effect of Nd: YAG pulsed laser emitting at 532 nm is more attenuated than that of excimer laser operating at 308 nm.
Keywords: ageing, cellulose, UV laser treatments.

The Influence of Some Chemical Agents Based on Natural Products on the Conservation of Some Lignocellulose Composite Structures

ELENA UNGUREANU, OVIDIU UNGUREANU, VALENTIN I. POPA

pages 157 - 166
Abstract
The analysis is made on the effect of some chemical substances based on natural products: unmodified/modified straw lignin chemically modified through hydroxymethylation, furan resin, as well as solutions that contain copper ions (copper chloride and tetraamminocopper hydroxide) on the conservation of some composite lignocellulose materials represented by fir wood and beech wood samples. The study has been made on the variety of humidity, the fluctuation of mass increase, the absorption variation of the protective product, as well as the water absorption in the membrane of the treated wood, with substance in three concentrations: 1, 3 and 5%. As a result of the analyses made, it has been noticed that the degree of conservation of the composites is influenced by a range of factors: the wood species, the type and the concentration of the chemical agent that has been used, as well as the mechanism of interaction of the chemical substances with the main components of the wood.
Keywords: conservation, lignocellulose composite structures, biocides systems, natural products, biodegradation.

Interaction of Proteins with Cross-Linked Poly(Vinyl Amine) Multilayers

ECATERINA STELA DRĂGAN, FLORIN BUCATARIU

pages 167 - 173
Abstract
Novel multilayer films consisting solely of cross-linked single component layers were generated by a selective cross- linking of the poly(vinyl amine) (PVAm) layers in [PVAm/poly(acrylic acid) (PAA)]n films constructed on silica microparticles or silicon wafers, followed by the removal of PAA. The adsorption of human serum albumin (HSA) on the single component multilayers was followed by UV-Vis spectroscopy, when the (PVAm)n films were deposited on silica microparticles. The surface topography of the (PVAm)n multilayer thin films deposited on silicon wafers, before and after the adsorption of HSA, has been studied by atomic force microscopy.
Keywords: poly(vinyl amine), layer-by-layer, human serum albumin.

Preparation and Swelling Behavior of Chitosan-Based Composite Hydrogels

ECATERINA STELA DRĂGAN, MARIA MARINELA PERJU

pages 175 - 180
Abstract
In an attempt to obtain fully cationic hydrogels with a good stability and high water uptake irrespective of pH, the simultaneous cross-linking of two polycations, one natural (chitosan) and another one synthetic, both bearing primary amine groups able to react with glutaraldehyde in aqueous medium was performed. The main parameters which controlled the properties of the composite hydrogels were: the molar ratio between polycations, and the concentration of the cross-linking agent. Information on the swelling mechanism of the gels was obtained from the study of the swelling kinetics.
Keywords: chitosan, cationic hydrogel, swelling ratio.

Ferrocene Containing Liquid Crystals

ROXANA MARIA AIOANEI, IRINA CÂRLESCU, DAN SCUTARU

pages 181 - 190
Abstract
The paper presents synthesis and structural characterization of some new ferrocenomesogens containing azo and ester linking groups. The compounds were obtained by reacting 4-alkoxybenzoic acid with 4-ferrocenyl-4’- hydroxyazobenzene.
Keywords: ferrocene, esters, azo aromatic compounds, ferrocenomesogens.

Thermosensitive Copolymers Obtained by Living Radical Polymerization

ANCA DANIELA HODOROG (RUSU), IULIAN NOR, NICOLAE HURDUC, CONSTANŢA IBĂNESCU

pages 191 - 198
Abstract
Living radical polymerization is one of the few methods that are available, in order to synthesize polymers with complex architectures and a narrow polydispersity index. The present paper describes few aspects concerning the synthesis and characterization of amphiphilic polymers such as poly (dimethyl acrylamide)-g- polysiloxane. Because the macromolecular chains contain both sequences of poly (dimethyl acrylamide) which has a hydrophilic character, together with a hydrophobic polysiloxane chain, these polymers has an amphiphilic character. Poly (dimethyl acrylic amides) sequences have indeed a special property, being able to react in the presence of thermal stimuli. Thus, depending on the existing conditions in the external environment, these sequences may adopt a linear or entangled conformation. If we associate these conformations with micelles structures, this could lead to an aggregation/disaggregation phenomenon, under thermal stimulation. The polymers were obtained by living radical polymerization using a polysiloxane macro-initiator containing chlorobenzyl groups in the macromolecular side chain. The used catalytic system was based on Cu (0) and 2, 2 '- bipyridyl. The reaction was performed in the presence of DMSO at 80°C. Polymers were characterized by 1H-NMR spectroscopy, thermal gravimetric analysis and differential scanning calorimetry. The conformational changes were revealed by rheological tests by studying the variation of loss and accumulation modules depending on temperature.
Keywords: thermo-sensitivity, self-assembly, living radical polymerization.

Study on Isolation and Characterization of Some Polyphenols from Agro-Industrial by-Products

IOANA IGNAT, H. FAUDUET, S. BOSTYN, M.I. POPA, IRINA VOLF, V.I. POPA

pages 199 - 207
Abstract
Phenolics are ubiquitous compounds found in all plants as their secondary metabolites. These compounds represents one of the most widely occurring groups of phytochemicals and they may act as phytoalexins, antifeedants, attractants for pollinators, contributors to plant pigmentation, antioxidants and protective agents against UV light, among others. For these reasons, a great effort has been made to provide highly sensitive and selective analytical methods for the determination and characterization of polyphenols occurring in different plant tissues. The aim of the present study is to ascertain the phenolic profile of two different agro-industrial by-products (olive oil waste water and vinasse)
Keywords: polyphenols, isolation, HPLC, ionic exchange.

Overview of the Water Footprint Concept Applied for the Efficient Use of Water Resources

SIMONA-ANDREEA ENE, CORINA PETRONELA MUSTEREŢ, CARMEN TEODOSIU

pages 209 - 218
Abstract
This paper analyses the concept of water footprint which has been developed in order to have an indicator of water use in relation to human consumption. The water footprint of a country is defined as the volume of water needed for the production of the goods and services consumed by the inhabitants of that country. The concept of water footprint is helpful for understanding human impacts on freshwater systems and also may serve as a basis for strategies adequately tailored for improving water balances between stakeholders (industry, agriculture and other types of water users). Issues such as local water shortages and pollution are better addressed by considering production and supply chains as a whole, and by addressing the water cycles problems especially those related to human consumption. This study presents an assessment of the major issues posed by the implementation of the water footprint concept for the river basin management, especially considering the actual challenges posed by the Romanian context.
Keywords: water footprint, water use, river basin management.

Assessment of Water Quality Evolution in the Prut-Bârlad River Basin

CLAUDIA COJOCARIU, IONUŢ CARAENE, GEORGE BARJOVEANU, CARMEN TEODOSIU

pages 219 - 228
Abstract
The need to approach in an integrated manner the water resources issues in the river basin came due to the related shortcomings of the limited and increasingly polluted water resources, unable to sustain an ecosystem and which must be divided between the needs and requirements of the society, many citizens still not having access to sufficient and safe water supply. This paper presents an assessment of water quality evolution in the Prut-Bârlad river basin between 2005 and 2007. The assessment considers 5 major water quality classes (I, II, III, IV and V) as defined by national legislation (Law no. 310/2004). Water quality analysis was realized by monitoring physico-chemical, hydro- morphological and biological parameters of the priority pollutants, considering the length of the river afferent to each quality class. The water quality parameters were monitored in relation to the main sources of pollution and included in a specific water quality class of each monitoring section. The study showed how the water quality in the Prut-Bârlad river basin evolved over the period of analysis in terms of water quality, river length of the associated class V being drastically reduced.
Keywords: Prut River, Bârlad River, river basin, water quality classes, water quality assessment.

2008, Issue LIV (LVIII), Fasc. 1

Use Polyethylene Glycol-Based Aqueous Two-Phase Systems for Selective Extraction of Zn(II) from Cobalt, Nickel, Iron (III) and Lead

LAURA BULGARIU, D. BULGARIU

pages 7 - 16
Abstract
An aqueous two-phase system of polyethylene glycol (PEG) and (NH4)2SO4 mixture using thiocyanate ions as extractants, is proposed for the selective extraction of Zn(II), from Co(II), Ni(II), Fe(III) and Pb(II). The aqueous two- phase systems are prepared by mixing equal volumes of 40% [w/w] PEG(1,500) solution and 40% [w/w] (NH4)2SO4 solutions with different pH, and are composed from a polymer-rich phase and a salt-rich phase. The experimental results showed that Zn(II) is quantitatively extracted into PEG-rich phase in the pH range 1.5...3.5, at a SCN- concentration higher than 0.04 mol/L, while the others ions (Co(II), Ni(II), Fe(III) and Pb(II)) were little extracted in these conditions. Cobalt and iron (III) ions were extracted to PEG-rich phase by about 23% and 27%, respectively, but they did not interfere the extraction of Zn(II). The competitive interactions between metal ions and extractant (SCY) or phase forming anion (SO42-) plays an important role in the extraction process. This method was used for the selective zinc extraction from zinc polluted soils samples from industrial zone of Jassy city (Romania). After extraction about 67% from Zn(II) was removed.
Keywords: aqueous two-phase systems, polyethylene glycol, selective extraction, zinc.

Analysis of Hydrodynamics and Mixing Behaviour of Liquid Phase in External-Loop Airlift Reactors

MARIA GAVRILESCU, RADU Z. TUDOSE

pages 17 - 38
Abstract
In order to obtain further information on the behavior and optimal design of external-circulation-loop airlift bioreactors, the liquid circulation velocity, gas holdup and mixing characteristics were studied using water and highly viscous pseudoplastic solutions in two external-loop airlift rectors on bench and pilot scale, considering various values of downcomer to riser cross sectional ratio, AD/AR as well as the presence of static mixers. The analysis of EALRs showed that hydrodynamic parameters, such as liquid circulation velocity and gas hold-up are interdependent and highly determined by the gas superficial velocity, which generate the circulation driving force in the contactors. Also, mixing time and axial dispersion are dependent on the circulation intensity as well as operating scale. It was concluded that the scale up process has to consider process, geometric and material variables.
Keywords: airlift, heterogeneous system, liquid velocity, mixing time.

Study of Axial Mixing in Pulsed Extraction Column

CRISTIAN HOROBA, LILIANA - DOINA HOROBA, STELIAN PETRESCU

pages 39 - 52
Abstract
A study of axial mixing in pulsed extraction column with sieve plates at a single liquid flow was presented in this paper. The distribution of residence time, P6clet number and axial dispersion coefficient were determined experimentally in the presence or absence of pulsations at different values of liquid flow rate. The obtained results emphasize how the pulsating amplitude and frequency as well as the liquid flow rate influence the distribution function of residence time, P6clet number and axial dispersion coefficient. Based on the experimental values of distribution dispersion and cellular model, distribution function of residence time was calculated. Comparing the calculated values with experimental data of E(θ) function, it can be concluded that these are in a good agreement.
Keywords: axial dispersion coefficient, extraction column with pulsations, extraction column with sieve plate, distribution of residence time.

Influence of UV Radiation on the Paracetamol Ozonation in Water

ILIE SIMINICEANU, MARIA BOBU, AYFER YEDILER

pages 53 - 66
Abstract
The degradation of a paracetamol solution (C0P =5 mmol.L-1) was studied in a bench-scale setup by means of simple ozonation (O3) as well as by the ozonation catalyzed with UV light (O3/UV) in order to quantify the influence of UV light on the degradation process. The efficiency was evaluated through five performance indicators: the conversion of paracetamol ( XP ); the degree of mineralization ( XToc ); the apparent first- order rate constant (kap); Hatta number ( Ha) and the enhancement factor (E). A kinetic assessment has been performed for both processes. The main advantage of the photo-ozonation compared to the simple ozonation can be described as an increased conversion (92% vs. 79% after 90 minutes). Despite the fact that a superior rate constant (> 54%) and a higher Hatta number (+ 24%) could be calculated, the process was still in the slow reaction kinetic regime (Ha < 0.3), with an enhancement factor which was not significantly increased. The obtained results are useful for the design and scale-up of the gas–liquid ozonation reactor.
Keywords: conversion, mineralization, rate constant, Hatta number, enhancement factor.

Synthesis and Thermal Behaviour of Brush and Star Polymers Obtained by Atom Trasfer Radical Polymerization Reactions

IULIAN NOR, GABRIELA LISA, N. HURDUC, VIOREL SANDU

pages 67 - 76
Abstract
Herein, we report the synthesis and thermal stability study of some brush and star polymers starting from polysiloxanes with chloro-benzyl groups in the side chain. The polymers that we have prepared are cyclic and linear polysiloxanes grafted with styrene, respectively copolymers (styrene-butyl acrylate) and styrenechloromethylstyrene. We tried further to observe how these macromolecular architectures influence the thermal stability of these polymers by using a combination of Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC).
Keywords: ATRP, polysiloxanes, thermal analysis, differential scanning calorimetry

Biotechnological Processes in Pulp and Paper Industry Enzyme Treatment of Chemical Pulp

MIHAELA-ALINA BORDEIANU, DAN GAVRILESCU

pages 77 - 86
Abstract
This paper presents the evolution of biological catalysts use in pulp and paper industry, especially xylanases which improve the conditions of less pollutant reactants use, assure less aggressive bleaching parameters (lower temperature and pressure, less aggressive pH) and advantageous conditions to treat pulp mill effluents. The use of biological catalysts in pulp bleaching processes justifies the concept of sustainable development in which a successful development is due to the reorientation of the industry to renewable resources and natural processes in order to pollution prevention, resource conservation and cost reduction.
Keywords: biodelignification, enzymes, pulp bleaching, environment.

Contaminated Sites Management. Case Study in Sălaj County

AURICA GREG

pages 87 - 96
Abstract
The soil is the aerated upper part of the lithosphere, found in continuous evolution under the influence of several pedo- genetic factors, being the superficial layer of the Earth in which the vegetal life develops. Unlike other environmental factors, the soil has a diminished self-cleaning capacity, and the residual time of the soil contaminants is relatively high. The research and practical experiences described in this paper refer to those terrain surfaces affected by the chemical pollution from the industrial waste storage zones. The activities in the industrial sector exert a continuous pressure upon the soil through: pollutant emissions, landfills - these can increase the soil acidity, overfertilize it, accumulate various types of heavy metals in it, such as Ph, Cu, Zn, Cd, all of these lowering the soil quality. Experimental results obtained performing studies and researches conducted in two metallurgic industry landfills are presented as follows. We assayed heavy metal concentrations and other indicators specific to this area through laboratory atomic absorption spectrophotometric methods as well as other analysis methods. The optimal solution for the elimination of the specific pressures exerted on the environmental factors by these facilities can be done not only putting to good use the valuable materials within the waste content, but also reintroducing the surfaces occupied by landfills into the economic circuit through ecological reconstruction works.
Keywords: soil, heavy metals, landfills, automonitoring, contaminated sites.

RADU Z. TUDOSE in memoriam

by S. IFRIM

pages 99 - 101

2008, Issue LIV (LVIII), Fasc. 2

Texture of a New Ammonia Synthesis Catalyst

ILIE SIMINICEANU, ZOLTAN ECSEDI, CRISTIAN BURCIAG, LAVINIA LUPA

pages 9 - 20
Abstract
A new iron-based promoted catalyst, designed to be charged into the industrial radial–axial flow reactor, was investigated in an Accelerated Surface Area and Porosity Analyser-Micrometrics ASAP 2020. The primary experimental curve was identified as an adsorption/desorption isotherm of type IV with H1 hysteresis. The main textural parameters (surface area, pore volume/porosity, pore size distribution (PSD) and average pore diameter) have been assessed usind six calculation methods: Langmuir model, BET equation, Single point method, t-Plot method, BJD adsorption, and BJH desorption. The surface area was between 12.33 m2/g (single point method) and 17.48 m2/g (Langmuir model). From BET surface area the t-Plot has shown that about 9% was due to micro-pores. The average pore diameter derived from BJH adsorption model was of 16.72 nm. The determined parameters predict a better activity of the new catalyst compared to the traditional one.

Waste Management and Pollution Prevention. I. Waste Electrical and Electronic Equipment

ANA-MARIA SCHIOPU, MARIA GAVRILESCU

pages 21 - 35
Abstract
Some aspects regarding waste electrical and electronic equipment collection and recycling are highlighted in the paper. Waste electrical and electronic equipment recycling is considered important subject not only from the point of waste management, but also from the recovery of valuable materials. European and national regulatory issues are revealed and then actual features of WEEE management are presented, considering Iasi city as a case study. Waste Electrical and Electronic Equipment (WEEE) Directive was shortly refereed along with the related Directive on Restrictions of the use of certain hazardous substances in electrical and electronic equipment (RoHS). In Romania, Governmental Decision 448/2005 is presented as the main regulatory act concerning WEEE. For the management of waste electrical and electronic equipment, manufacturers may be associated or can act as individual organizations (according to Ministry Order 1225/2005 for approval of the procedure and criteria for evaluation and authorization of collective organizations in taking over responsibility for achieving annual targets for the collection, reuse, recycling and recovery of waste electrical and electronic equipment). In Iasi City, the door-to-door collecting system was successful, as well as WEEE collecting at established points.

Chlorophenols Degradation – an Overview

CAMELIA SMARANDA, LAURA–CARMEN APOSTOL, FLORENTINA–ANCA CĂLIMAN, MARIA GAVRILESCU

pages 37 - 48
Abstract
The degradation of chlorophenols has been shortly reviewed in this paper, including the combined electrochemical reduction and oxidation, photochemical transformations in aqueous solutions as well as biodegradation. Dechlorination is the first critical step in the bacteria degradation of many chlorinated pollutants. The chlorophenols-degrading microbes, with special emphasis on degradation mechanisms, were highlighted. The mechanism of biodegradation depends on the process conditions. Under the aerobic condition, degradation of mono- and dichlorophenols was shown to be initiated by oxygenation. Anaerobic biodegradation of chlorophenols occurs by reductive dechlorination, a process by which chlorines were replaced with hydrogen. Some systems for buodegradation were presented, as well.

Surface Tension and Excess Thermodynamic Properties of Binary Mixtures Isopropanol–Water and n-Butanol-Water

GABRIELA LISĂ, DANIELA APREUTESEI, CĂTĂLIN LISĂ

pages 49 - 54
Abstract
Surface tensions, σ, of liquid binary mixtures iso-propanol – water and nbutanol – water were measured at 294.15, 304.15 and 311.15 K and normal atmospheric pressure. Based on these experimental data we calculated the excess surface tension of the studied systems. The results were fitted to a Redlich-Kister type polynomial relation, and the corresponding parameters have been derived. The results are discussed in terms of molecular interactions

Characterization of Layered Double Hydroxides as a Delivery Vehicle for Oxacillin

SOFRONIA DRANCA, GABRIELA CARJA, N. APOSTOLESCU GABRIELA CIOBANU, I. BALASANIAN

pages 55 - 62
Abstract
Intense research interests have carried on layered double hydroxides (LDHs) mainly due to the ability of the anionic clay matrices to incorporate, to transport and targeted various bio–and organic molecules. The ensemble: clay matrix – therapeutic agent is able not only to join the properties of its components but also to develop its own characteristics in a single material. We present in this work the controlled synthesis and physical–chemical characterization of a new drug delivery system based on oxacillin incorporated in the layered matrix of hydrotalcite-like anionic clays. The structural properties of the drug–clay assembly are described by using the results of X-ray diffraction (XRD), infrared spectroscopy (FTIR) and thermal analysis (TG-DTA). The antibiotic release from the clay matrix points out that a rapid release of the drug during the first 30 min is followed by a more sustained one. The results suggest that the oxacillinlayered double hydroxides can be used as an effective drug delivery system with improved drug stability.

The Biodegradation of Some Composite Structures in the Presence of Some Biocides Systems Based on Natural Products

ELENA UNGUREANU, OVIDIU UNGUREANU, VALENTIN I. POPA

pages 63 - 72
Abstract
The paper analyses the biodegradation of some natural composite structures represented by fir and beech wood, investigated in both treated and untreated state, on the surface of the samples. The treatment has been applied through brushing in both directions. The products used for the treatment, in different concentrations (1%, 3%, 5%), are both of organic (unmodified and modified straw lignin, furan resin) and inorganic origin (copper chloride and copper–ammonia solution). Biodegradation, followed in several variants, selected according to their aspect, illustrate the standard classes of biological risk to the biological attack. The biodegradation and the bioprotection levels were tested in different environments, namely indoors, outdoors, buried in the soil (in the absence of plants) and in a soil cultivated with bean plants (Vera variety). The role of these tests was to establish the efficiency of the treatment applied on the wooden material depending on the type of the product used. The main parameters followed in these experiments were: mass loss and wetting angle.

Synergistic Reactive Extraction - Alternative for Carboxylic Acids Extraction

LENUŢA KLOETZER, ANCA–IRINA GALACTION, DAN CASCAVAL

pages 73 - 87
Abstract
Extraction of the carboxylic acids using one extractant or diluent is costly and laborious without obtaining high extraction efficiency. The extraction systems with combined extractants and diluents had lead to major increase of extraction yield compared with systems using single extractant or solvent. This paper presents a review of the extraction studies of some carboxylic acids (lactic, succinic, propionic and tartaric) with synergistic combinations. The influence of different extractants and diluents indicated that usually synergistic reactive extraction with mixed tertiary amine and polar solvents leads to high extraction efficiency for the studied acids. Also, high extraction efficiency was obtained for the system with mixed tertiary amine with long chain / tertiary amine with short chain and for mixture of polar and non- polar diluents. The study of extraction mechanism and characterization of different components of the extraction system (carboxylic acid, diluents, extractants) represents an important step for designing the optimal synergistic reactive extraction system for a given solute.

2008, Issue LIV (LVIII), Fasc. 3

Sources of green energy in pulp and paper industry. I. Pulp mill solid wastes

D. GAVRILESCU, GR. CRĂCIUN, GH. DUŢUC

pages 7 - 16
Abstract
Pulp and paper industry expresses an interest in adapting and integrating advanced biomass energy conversion technologies into its mill operations. Industrial adoption of these new technologies has the potential for higher efficiency, lower capital cost, and safer operation than conventional operations that burn fossil fuels for energy. Incineration with energy recovery has the advantage of hygienic disposal, volume reduction, and the recovery of thermal energy by means of steam or super heated water that can be used for heating and power generation. Pulp mills generate various quantities of energy-rich biomass as wastes, depending on technological level, pulp grades and wood quality. These wastes are produced in all stages of the process: wood preparation, pulp manufacture, chemical recovery. Energy recovery from wastes of different origin, has become a generally accepted alternative to their disposal. The paper reviews the current state and tendencies in using as a fuel of solid wastes generated in pulp mills. A description of biomass-derived wastes regarding their opportunity to be used for energy recovery is presented. The heating properties of wood wastes as a fuel are also presented.

Contributions regarding reducing of the atmospheric air pollution by retaining the gas pollutants from the process of sulphur extraction

A. GREC

pages 17 - 26
Abstract
The present work proposes to bring a solution regarding the problem of SO2 şi H2S atmosphere pollution, extremely toxic gases resulted from the process of extracting the technical sulphur from the bedding of E. M. Călimani. The research has started from laboratory stage (lab experiences of the gas absorption methods) being consequently extended to pilot scale and in the end to the building of the presented industrial installation. The installation was built and experienced in the above mentioned technological flow, with the following performances: decrease of the pollution level through the withhold of the SO2 and H2S in absorbant solution (the iron – soda method), the retain efficiency values being in average ηab SO2 = 72,69% and ηab H2S = 61.06%. At a production of around 150 – 200.000 t/year extracted ore results a decrease of the SO2 and H2S emitted in the atmosphere of around 1,565.8 kg/year SO2, respectively 412.62 kg/year H2S, thus considerably reducing the pollution of the influence zones and the risk of the nearby population diseases. Besides the ecological aspect, they can benefit from economic advantages such as: fuel saving up to 2,5 –3,5 tones fuel oil/a day (through increasing the energy efficiency) and last but not least, obtaining the secondary product, Na2SO3, around 9,5 t/year, used as raw matter in other industrial processes (medicine, leather goods, photographic industry, etc.). Another advantage is the simultaneous retaining of the two pollutants (SO2 şi H2S) from the pollutant emitted. We consider that the method presented hereby, although a small step in the horrendous fight with the destructions provoked by pollution, consists in a “step forward” and can be applied as well in other pollutant industrial processes.

A survey of thermal behaviour of some hetero-organic polymers with controlled architecture

V. HURDUC, G. LISĂ, M. LUNGU

pages 27 - 38
Abstract
The present research is focused on thermal analysis in dynamic conditions of some new polymers based on polysiloxanes grafted with a binary copolymer based on styrene – butyl acrylate and a tertiary copolymer based on styrene-butyl acrylate–methyl methacrylate. Thermal analysis in dynamic conditions (TG, DTG and DTA) was performed and STARe software was used. The results confirm a high thermal stability up to 350°C. The mechanism of degradation is radical by depolymerisation and transfer of intermolecular chains, the degree of depolimerization being determined by the nature of the components.

Aspects concerning some biocides systems based on natural aromatic compounds and their copper complexes

E. UNGUREANU, A.-M. CĂPRARU, V. I. POPA

pages 39 - 46
Abstract
This work shows the results regarding the biological stability of the birch veneer in the presence of some natural compounds having different levels of chemical modification and of their copper complexes. The products used for the treatment in a 5% concentration in 0.1N ammonia solution have been: the chemically modified/unmodified straw lignin, along with copper compounds (copper chloride and copperammonia solution) unbound or combined with natural compunds. The biostability tests have been perfomed by burying the samples treated with the mentioned products in the soil. The level of biostability has been estimated through burial in the soil for six months and through the values of the wetting angle. The obtained data have emphasized that the effectiveness of the applied treatment depends on the character of the utilized product, on the modifying method and on the capacity of complexing with the copper ions.

Decorative protection of carbon steel through black finishing at low temperatures. 1. Technological parameters

L. LAZĂR, F. BANDRABUR, A. SZÉP

pages 47 - 58
Abstract
Black finishing is a decorative-protecting process of the carbon steel based supports, prepared from alkaline solutions, in the presence of some oxidizing agents. The achieved thin film may be bright or lustreless, exhibiting a colour that varies from black to brown due to the formed iron oxides. The technologic regime changes in function of the nature and composition of the solution, as well as the nature and the surface state of the metallic support. In this paper, it was studied the influence of the factors that may affect the quality of the thin film formed by black finishing of the steel at temperatures lower than 100°C, avoiding thus the vaporization of water and the concentration of the solution. The quality of the oxides thin film was investigated considering the nature of the metallic support and the quality of mechanical finishing previously to black finishing process, the nature and quality of black finishing solution (unsaturated /saturated with iron ions); temperature and duration of the process; solution hydrodynamic regime. It was demonstrated that the oxides thin film formed through black finishing of OLC meets the quality requirements if the process is operated by stirring of the solution for 35 minutes at temperatures between 85…88°C.

Qualitative and quantitative aspects of voltammetric behaviour of the Cd2+ ion

D. BEJAN, A. DUCA

pages 59 - 68
Abstract
The present paper deals with qualitative and quantitative study on the voltammetric behaviour of the Cd2+ ion (CCd2+ = 10-6…5·10-6 mol/L) on different electrodes: carbon paste electrode (CPE) and carbon paste electrodes modified with cation exchanger (NAFION) either deposited as thin film on the surface (NAFION coated carbon paste electrodes – NC-CPE) or entrapped within the carbon paste (NAFION entrapped carbon paste electrode – NE-CPE). The following parameters have been taken into account: the electrode type, the Cd2+ ion concentration, the concentration time by electrodeposition and the ion-exchange pre-concentration time at a constant potential (Econc. = -1.1 V and -1.3 V) by using a non-complexing support electrolyte (10-1 mol/L acetate buffer, pH = 4.5). The obtained cyclic and ion-exchange voltammograms were supple, showing clear anodic and cathodic peaks. The process electrochemistry is quasi- reversible. The intensity of the anodic current, as a signal of analytical interest, increases rather proportionally with the increasing concentration of Cd2+ ion (within the concentration range under consideration) and concentration time (no longer than 5 minutes) and depends on the electrode nature. The method can successfully be applied for estimating the low Cd2+ concentration in waters, animal and vegetal tissues as well as in food.

Quality initial analysis of the ground waters of the metallurgical platform area in Cordun

E.-D. CÂRLIG, M. MACOVEANU

pages 69 - 80
Abstract
The goal of the present article is the study of the ground waters of the Cordun area – the waste dump. It is about the characteristics of the analyzed site (general considerations, climate elements, temperature and precipitations, hydrological elements, region hydrogeology) and at the establishment of the pollution rate of the ground water in the studied area (the pressures to which the water body is forced, experimental data, results and debates). The conclusion drawn at the end of this article is that the studied area presents a significant pollution rate of the ground waters.

Studies regarding onto solid materials based on coal ashes

D. ŞUTEU, C. ZAHARIA

pages 81 - 90
Abstract
Some batch sorption experiments were carried out to remove Methylene Blue cationic dye from aqueous systems using industrial coal ash and other solid materials based on ash and lime as a low cost sorbent (e.g., Ads 1h, Ads 2h, Ads 3h and Ads 4h). To establish the most suited type of solid materials to be used as sorbent for this dye, the data were analyzed using the Langmuir, Freundlich and Dubinin-Radushkevich models for the sorption isotherms. The results of this experimental study show that all tested solid materials have a limited capacity for dye molecules uptake but we also observed that the sorbent named Ads 1h presents the best values for the sorption capacity.

Voltammetric study on the Cd2+ - Cu2+ and Cd2+ - Pb2+ Binary Systems

D. BEJAN, A. DUCA

pages 91-104
Abstract
The present paper is aimed to report the qualitative study on the voltammetric behaviour of the Cd2+ - Cu2+ and Cd2+ - Pb2+ binary systems in slightly acid (10-1mol/L acetate buffer, pH = 4.5) solutions of 10-6…10-4 mol/L concentrations, on carbon paste electrode (CPE) and CPE electrodes modified with NAFION (NAFION coated carbon paste electrode: NC-CPE, and NAFION entrapped carbon paste electrode: NP-CPE). The influences of ion concentrations, the ionomer presence within the electrode material, and the interferences of the Cu2+ and Pb2+ ions on the Cd2+voltammetric behaviour were followed. Qualitative and quantitative information on the Cd2+ voltammetric behaviour on the same electrodes and under similar experimental conditions is to be found in a previous paper [19]. The obtained experimental results are in good agreement with literature data.

2008, Issue LIV (LVIII), Fasc. 4

Airlift Bioreactors

ROXANA BALTARU, ANCA-IRINA GALACTION, DAN CAŞCAVAL

pages 9 - 28
Abstract
Biotechnology is currently a rapidly expanding field of interdisciplinary research. This is evident from the development of a large number of new types of bioreactors. The traditional stirred tank bioreactor is no longer a priori the standard bioreactor, mainly because of economic considerations and the intrinsic properties of the bio-phase used. Air-lift bioreactors are a relatively new type of fermentor, offering several advantages for large-scale aerobic bioprocesses, for animal and cell culture in particular. In many cases, the immobilized biocatalysts or microorganisms are used. This paper presents a general approach of the pneumatic bioreactors, and of the airlift ones in particular, from the viewpoint of the transfer processes and of the main domains in which they could be use.
Keywords: pneumatic bioreactor, airlift bioreactor, oxygen transfer, hydrodynamics

The Evolution In Time Of The Quality Of Ground Waters From The Area Of The Metallurgical Platform Cordun

ELENA – DOINITA CARLIG, MATEI MACOVEANU

pages 29 - 42
Abstract
This article is intended to study the quality in time of the ground waters from the region Cordun – the waste dump. It refers to the characteristics of the location studied (climate elements, temperature, precipitation, the hydrogeology of the region), establishing the degree of pollution of the ground water from the area studied (the pressures the water surface has been subject to in time, experimental data, results and discussions). The conclusion of this article is that the area we studied presents a significant pollution of the ground waters.

Sources Of Green Energy In Pulp And Paper Industry. Part II: Paper Mill Solid Wastes

DAN GAVRILESCU, GRIGORE CRACIUN, GHEORGHE DUTUC

pages 43 - 54
Abstract
Paper mills generate various quantities of energy-rich biomass as wastes, depending on technological level, and paper grades. These wastes are produced in all stages of the process: pulp processing, paper manufacture, recycled paper processing, waste water treatment. Energy recovery from wastes of different origin, has become a generally accepted alternative to their disposal. The paper reviews the current state and tendencies in using as a fuel of solid wastes generated in paper mills. The heating properties of rejects from recycled paper processing, paper sludge, and low- quality recovered paper grades are also discussed. Some aspects of emission of greenhouse gases (GHG) are also presented.
Keywords: paper mill, solid wastes, rejects, recovered paper environment

The Viscosity and Density of The Aqueous Solutions Used For The Absorption Accompanied By Chemical Reaction

MARIA HARJA, LACRAMIOARA RUSU, MARINELA BARBUTA

pages 55 - 62
Abstract
This paperwork based on a large number of experimental data suggest mathematical relations obtained by the regress with a view to calculate the viscosity the solutions like Na2SO4 (sodium sulfate), KOH-K2CO3 (hydroxide caustic potash- carbonate potash) and KHCO3-K2CO3 (carbonate – bicarbonate potash). For potash and bicarbonate potash we establish mathematics relations of densities. By calculating the viscosity with these equations the maximum error is 3.93%, and for the density the error is below 2%.

Corrosion Behaviour Of A HSLA Steel As A Function Of Immersion Time In Natural Seawater

MARIA LUNGU, NECULAE. AELENEI, DANIEL MARECI, ROMEO CHELARIU

pages 63 - 74
Abstract
The corrosion behaviour of a high strength low-alloyed (HSLA) steel in seawater has been studied as a function of immersion time over a period of 90 days. Electrochemical and microscopic studies relieve a general no uniform corrosion, the corrosion rate depending on immersion time. The corrosion product is a porous and not very protective layer of iron oxy-hydroxide. A maximum protection there was pointed out for the sample held 45 day in seawater. The linear polarization curves point out that the thermodynamic tendency of corrosion is higher when the sample is maintained in natural aerated seawater. The cyclic polarization curves reflect a direct dependence between corrosion rates and applied over potential. The slopes of the linear portions depend sensible on immersion time in seawater and generally reflect the same tendency of variation as the instantaneous corrosion currents
Keywords: HSLA steel, seawater corrosion, corrosion potential, linear polarization, cyclic polarization

Biophysico-chemical processes of heavy metals in soil environments

VASILE LUCIAN PAVEL, RALUCA MARIA HLIHOR, FLORENTINA ANCA CĂLIMAN, MARIA GAVRILESCU

pages 75 - 87
Abstract
Considering the complexity of soils and the interactions generates between soil components and other elements, like heavy metals coming from polluting sources, this paper reveals some aspects referring to biotic and abiotic interactions of metals with soil mineral and organic colloids, which have a major impact on the physics, chemistry, and biology of soil and surrounding ecosystems. The cleanup of soils polluted by hazardous metal contaminants has become a matter of urgent public concern since metal contaminants in soils affect their production potential and biodiversity. Sorption is considered as a major process controlling the partitioning of metals between the aqueous and solid phases in soils. As a method for remediation, biosorption is based on the fact that large concentrations of metals are frequently associated not only with living microbial biomass but also with dead cells, for example microbial biopolymers that have the ability to bind metals.
Keywords: bacteria, biosorption, contamination, interfacial interactions metals, organics, remediation

New Composite Materials Used As Adsorbents For Water Vapours

STELIAN PETRESCU, MARIUS SEBASTIAN SECULA

pages 89 - 96
Abstract
Several investigations approaching the achievement and characterization of some composite adsorbent materials for water vapours are presented in this paper. Thus, eight new types of composite materials were synthesized by impregnating silica gel, active carbon and alumina respectively with aqueous solutions of calcium chloride or lithium bromide. Then, the composite materials were characterized using high-accuracy equipment.
Keywords: composite adsorbent material, water vapour adsorption, silica gel, active carbon, alumina.

New Complex Compound Of Cu(Ii) With Ligand Derived From 1-(5-bromo-2-hydroxy-4 methyl phenyl)-2 naphtylsulphanyl)-ethanone

DOINA SIBIESCU, IOAN ROSCA, TURCUMAN (ANTIGHIN) SIMONA

pages 97 - 104
Abstract
In this paper it is presented the obtaining reaction of a new complex from interaction of Cu(II) with 1-(5-bromo-2- hidroxy-4 methyl phenyl-2 naphtylsulphanyl)-ethanone in molar ratio of 1:2 and it's characterization by different methods as: chemical analysis, thermo-gravimetry, IR absorption spectroscopy, RES, and X-ray diffraction. The new complex crystallizes in the triclinic system with hexacoordinated central atoms Cu(II) with octahedral structures. The obtaining reaction of the new complex can be used in gravimetric determination of Cu(II) with an error of ± 0,31%.
Keywords: Cu(II), 1-(5-bromo-2-hidroxy-4 methyl)-2 naphtylsulphanyl)-ethanone, reagent of precipitation

2007, Issue LIII (LVIII), Fasc. 1-2

Analytical evaluation of the composition - quality correlation in wines

D. BEJAN

pages 7 - 18
Abstract
The aim of this paper is to accomplish a chemical-analytical characterization of several wine samples (white, red, rose) obtained under different technological conditions as well as ascertain the composition-quality correlations. The following parameters were taken into account: pH, rH, redox potential, electrical conductivity, content of tanning compounds, concentration of macro- (Na, K, Ca) and micro- (Fe) elements. As made evident by the experimental run, all the samples under study showed normal chemical characteristics in agreement with literature data. Different modifications (clearness, colour, taste) in function of the wine type, were noticed along the preservation time. The wines of high iron content, where Fe3+ percentage is higher, with lower acidity and inadequately treated with SO2, showed the most-significantly modifications. The colour variations in time were estimated qualitatively and quantitatively by means of VIS molecular absorption spectra, both with white and red wines.

Studies on the kinetics and the mechanism for the synthesis process of some coordination polymers of Cr(III).

I. ROSCA, D. SIBIESCU, G. CARJA

pages 19 - 24
Abstract
The paper presents the mechanism and the kinetics of the reactions between the Cr(III) acetyl-acetonates with ethyl- naphtyl-phosphinic, ethyl-naphtyl-thiophosphinic and ethylnaphtyl-dithiophosphinic acids. The possible reaction mechanism assumes the substitution of acetyl-acetonate ligands with the anions of the reacted acids. In the beginning we assumed this process as a first order nucleophilic substitution (SN1); this corresponds to the lowering of the central atom's coordination number with a unity, due to the removal of one ligand of the CrAcac3 molecule. Next step is to study this process as a second order nucleophilic substitutions (SN2); this means the increasing the number of the ligands through the coordination of the substituted ligands to the central atom followed by the quick elimination of the substituted ligand. The obtained results point out that the mechanism of the studied reactions is of type SN2.

The Zn(II) extraction in peg-based aqueous two-phase systems using tiocyanate ions as extracting agents.

L. BULGARIU, D. BULGARIU

pages 25 - 32
Abstract
The Zn(II) extraction behaviour was studied in aqueous polyethylene glycol (PEG)- (NH4)2SO4 two-phase system in presence of SCN- ions, as a function of several experimental parameters. For a system prepared by mixing equal volumes of 40% (w/w) PEG (1,550) with 40% (w/w) (NH4)2SO4 aqueous solutions, Zn(II) remain almost exclusively in the salt-rich phase. The variation of salt stock solution pH does not change too much the Zn(II) extraction efficiency. The addition of tiocyanate ions to these systems determined a quantitative Zn(II) extraction to the PEG-rich phase. The Zn(II) extraction efficiency depends on the salt stock solution acidity and on the concentration of tiocyanate ions added into system.

Coordination compounds of Ni(II) tetracoordinates with organic ligands

M. FLONDOR, I. ROSCA, D. SIBIESCU

pages 33 - 38
Abstract
The synthesis and study of some coordination compounds derived from the interaction of Ni(II) with 2-(4-chloro- phenylsulfanyl)-1-(2-hydroxy-3,5-diiodo-phenyl)-ethanone (L1), 1-(5-bromo-2-hydroxy-4-methyl-phenyl)-2-4-chloro- phenylsulfanyl)-ethanone (L2) and 2-(4-chloro-phenylsulfanyl)-l-(3,5-dibromo-2-liydroxy-pbenyl)-ethanone (L3) is performed. The applied methods in this study are: chemical analysis, IR-absorption spectra and ESR spectroscopy. Based on experimental data and on literature indications, the structural formulas of these compounds are assigned.

Mathematical modelling of anodic processes with soluble electrode in diffusional regime.

M. S. SECULA, S. PETRESCU

pages 39 - 52
Abstract
A mathematical model valid in diffusional regime for anodic dissolution processes by rotating disk technique is proposed. The model was used to determine the distribution of copper ion concentration in the diffusion boundary layer at the dissolution of copper disks in copper sulphate solutions. Copper disks of 0.01 m in diameter, angular speed values situated in 10...3,000 rot/min range, copper ion solution concentration C∞Cu2+ from 1.587 to 62.5 g/L, and temperature between 20° and 60°C were considered in calculations. Based on the mathematical model the copper anodic dissolution rate and limiting current density were determined. The mathematical model obtained was validated using Levich equation.

The activity of a heterogeneous photo- fenton catalyst at different thermal aging regimes

B. IURASCU, I. SIMINICEANU, M. VICENTE

pages 53 - 58
Abstract
A new photo-Fenton catalyst has been manufactured from synthetic layered clay laponite (Laponite RD) by the pillaring technique Eight different catalyst samples were prepared: four without thermal aging (WTA), calcined at 523 K, 623 K, 723 K and 823 K, and other four with thermal aging (TA), calcined at the same temperatures. The samples were characterized by XRD and SEM/EDS techniques, and through the bulk chemical analysis. The activity of catalyst samples was evaluated in the phenol degradation by the photo-Fenton process, using an aqueous solution of 0.1 mM concentration in phenol by the phenol conversion (XPh) and phenol mineralization (XTOC) versus reaction time in the presence of 5 mM H2O2, 1 g/L catalyst, pH = 3, and 303 K. A new kinetic model has been proposed and tested, and the corresponding two kinetic constants have been identified. The other operating factors have been kept constant at optimal values previously found: 5 mM H2O2, 1 g/L catalyst, pH = 3, and a degradation temperature of 303 K. The activity of each catalyst sample was evaluated through the apparent first order rate constant derived from the experimental kinetic curves. The best results were obtained with the TA-623 catalyst.

Preparation and characterization of mgal layered double hydroxides containing interlayer organic p-methoxybenzoate.

A. BOTOMEI, E. DUMITRIU, V. HULEA, A. NASTRO

pages 59 - 66
Abstract
Layered organic-inorganic hybrid composites, containing anisic acid (AA) as guest within the interlayer gallery of MgAl-layered double hydroxide, were prepared by three different synthesis techniques: (i) direct synthesis by coprecipitation of the metal nitrates and sodium AA, (ii) direct ion exchange of the LDH nitrate with the organic anion and (iii) by the structure reconstruction of the LDH previously calcined at 500°C. In all the cases, direct evidence for the intercalation is obtained from XRD data, when a noticeable increase of the interlayer distance was observed. Thus, powder X-ray diffractograms of these materials show that the basal spacing of MgAl-layered double hydroxide with carbonate as the counter anions expanded from 7.71 to around 18 Ain the resulting hybrid material. Also, IR studies show that the absorption bands of the resulting materials correspond to both the characteristic functional groups of the host and the guest. Therefore, when the two results are taken together, the expansion can be evidently attributed to the intercalation of the AA anions in the inorganic interlamella for the formation of the hybrid material. The intercalation of AA is also confirmed by thermogravimetric analysis (TG).

Synthesis of 1-[n-(m-nitrobenzoyl)-a-l-glutamil]- 5’,6’-dimethyl-benzimidazole and its immobilization by esteric bonds on polysaccharides.

D. DUMITRAS, M. POPA, V. SUNEL

pages 67 - 84
Abstract
This paper studies the synthesis and the dicyclohexyl carbodiimide activated immobilization reaction through ester-type covalent bonds of an oxazolone derived from N-(m-nitrobenzoyl)-L-glutamic acid, ring opened with 5,6-dimethyl- benzimidazole on polysaccharides (gellan, xanthan and alginic acid sodium salt). The maximal efficiency of coupling reaction was obtained for the active principle-gellan system. For this system was realized an experimental program varying the following parameters: molar ratios DCCI/medicament and medicament /gellan as well as the reaction duration. To achieve a maximum content of biologically active product in immobilization compounds, the parameters' highest values are used. The kinetics of the drug's release from the supports are studied under alkaline hydrolyse conditions.

Slurry reactor for heterogenous photocatalytic degradation of reactive orange 16.

A. F. CĂLIMAN, A. ANTONIADIS, I. POULIOS, M. MACOVEANU

pages 85 - 94
Abstract
The degradation of textile dye Reactive Orange 16 by the use of heterogeneous (TiO2- mediated) photocatalytic method under artificial irradiation has been studied into a slurry photoreactor with recirculation of suspension. Influence of few different conditions was first tested in order to find the proper amounts of dye and catalyst concentrations, as well as of the oxidizing agent, to be used for the further experiments. Effect of reused catalyst was also described. Electric energy consumption was calculated and compared for two different systems.

Chemischer Zerfall von Alten Kollagenträgermaterialien.

N. MELNICIUC PUICA, D. DOROHOI, A. CECAL

pages 95 - 102
Abstract
This paper deals about collagenic material chemical degradation. Atmospheres rich in sulphur dioxide have a proven noxious influence upon the lastingness of old parchment and leather. Absorption of water vaporous vs. time exposure for different samples (exposed to different concentrations in SO2 during different periods of time) was studied. Experimental results were processed according to polynomial models and correlation between variables was graphically represented.

Some aspects regarding the use of near infrared analysis of Apple fruit

A-S. SERBAN, E. BOBELYN, B. NICOLAI, M. NICU

pages 103 - 108
Abstract
For the quality measurements, post-harvest apples (Halos dornestica Borkh.) of different varieties and origins were studied: Golden (Belgium, South Africa, Italy and France), Royal Gala (Chile, Argentina and New Zeeland), Jonagold (Belgium - different producers), Braeburn (South Africa, Chile, France and New Zeeland), Pink Lady (Chile, Argentina, France, South Africa and New Zeeland) and Fuji (China). A NIR spectrum was collected from the red and green side of each apple and the reference quality parameters Magness Taylor firmness and soluble solids content (SSC) were measured destructively. The spectral data were analysed by means of partial least squares regression. The best correlation for the sugar content was obtained in Golden apples (RMSEP = 0.63°Brix) and the best correlation for firmness was observed in Braeburn apples (RMSEP = 6.35 N). The measurements will continue on other apples origins in order to obtain a highest variability of the experiment.

On lignin reactions in oxygen based kraft pulp bleaching.

A. C. PUITEL, A. BORDEIANU, D. GAVRILESCU

pages 109 - 122
Abstract
Kraft pulp bleaching consists both in delignification and removal of chromophores. Lignin removal represents the most important objective in bleaching, since lignin is the most important contributor to the cellulose kraft pulp colour. Industrial scale bleaching is performed with the help of chlorine (Cl2), chlorine dioxide (ClO2) and oxygen based bleaching agents - molecular oxygen (O2), hydrogen peroxide (H2O2), ozone (O3) and peracids. Chlorine bleaching has been considered polluting, since it has produced large quantities of chlorinated organics. Chlorine has been replaced with chlorine dioxide, which has the advantage of being highly selective delignifying agent. The disadvantage of using ClO2 for bleaching and delignification, besides production costs for ClO2, is that chlorinated organics are still produced, even if at lower levels. This is the reason why, from an environmental point of view totally chlorine free (TCF) bleaching seems more attractive. Lignin reactions with the oxygen based bleaching agents are the primary condition for lignin fragmentation and further removal from the ligno-cellulosic complex. Lignin fragmentation is a direct result of species present in the oxygen based bleaching systems including ozone (O3), molecular oxygen (O2), superoxide radical (O2.-), hydrogen peroxide (H2O2), perhydroxyl radical (HOO.) and hydroxyl radical (HO.). The action of oxygen based delignification and bleaching reagents over lignin involves: hydroxylation, hydroxyl substitution, side chain oxidation, side chain cleavage, cleavage of the ether linkage, aromatic ring cleavage, and oxidative coupling. Oxygen based bleaching is a very sensitive process towards the presence of 'transition metal ions, which can catalyse the formation of hydroxyl radical, responsible for cellulose degradation during bleaching.

Aspects of the impact on the environment induced by industrial activities in Vaslui City 2. The impact owed to S.C. ILVAS S.A. VASLUI.

L. CEZAR, M. NICU, C. HUŢUPAŞ, F. APOSTU

pages 123 - 130
Abstract
In the context in which the evaluation of the impact of the industrial activities on the Environment became a main objective of the Environmental Politics, the discovery of more objective methods of the impacts quantification is highly requested. This paper is part of a cycle which stands for the thoroughness of some ways to make the impact evaluation more objective. It studies the problems specific to a milk industry unit and explains the impact up and down the river.

A novel computer-assisted approach using geographic information system and digital image analysis to estimate differences in concentrations of heterogeneous dispersed particles in solutions.

A-I. PETRIŞOR, A. W. DECHO

pages 131 - 136
Abstract
Quantification of heterogeneous dispersed particles in solutions or within a matrix has been a challenging task, especially those involving microscopic particles. An approach was developed here, that utilizes Geographical Information Systems (GIS) and digital image analysis, coupled with confocal scanning laser microscopy (CSLM) to estimate concentrations of microscopic particles (fluorescent polymeric microspheres and bacterial cells). We propose that the area occupied by particles within each image can be used as an alternative to traditional counting to estimate concentrations of homogeneously sized particles. Results indicate that the new approach performs as well as the traditional one, and represents the only methodology in special situations.

CONSTANTIN CALISTRU in memoriam

by I. SIMINICEANU

pages 137 - 138

2007, Issue LIII (LVII), Fasc. 3-4

Densities, viscosities, refractive indices and excess thermodynamic properties of binary mixtures propionic acid –toluene

G. LISA, D. APREUTESEI, C. LISĂ

pages 7 - 14
Abstract
Density, viscosity and refractive index have been experimentally determined for binary liquid mixtures toluene + propionic acid at 292.15, 299.15, 305.15, 311.15 and 317.15 K and normal atmospheric pressure. Based on these experimental data, we calculated the excess thermodynamic properties: the excess molar volume, viscosity deviations and the refractive indices deviation of the studied system. The obtained results have been discussed and interpreted in terms of the type and nature of the specific intermolecular interactions between the components.

Mass transfer study at gas separation by adsorption.

S. PETRESCU, I. MĂMĂLIGĂ, I. GALBEN

pages 15 - 24
Abstract
A mathematical model for the gas—solid adsorption in fixed bed of solid. in dynamic regime, is proposed. This model is valid for isothermal adsorption and allows to calculate the distribution of the water concentration in solid and gaseous phases as a function of time and the fixed bed height. On the basis of proposed model and of the experimental values of mass transfer coefficient, the water content in silica gel spheres was calculated. It was also presented the distribution of the water concentration on the height of a fixed bed of adsorbent at different times of adsorption. The obtained results allow to elucidate the kinetics of adsorption in a fixed bed and to calculate the local sorption rate.

Equilibrium and diffusion close to glass transition temperature in toluene – polystyrene systems.

I. MĂMĂLIGĂ

pages 25 - 32
Abstract
The results of an experimental investigation concerning the estimation of phase equilibrium and diffusion coefficients of toluene in polystyrene close the glass-transition temperature is presented. From successive differential sorption experiments it was found that close the glass-transition temperature "anomalous" non-Fickian diffusion of organic solvents in polymers occurs. This behaviour can be caused by the difference between the time scale for molecular reconfiguration (relaxation time) and the time scale of diffusion.

Investigation of the kinetic parameters of the VOCs oxidation process on SCR-DeNOx commercial catalyst. 2. Estimation of apparent activation energy.

L. LAZĂR, H. KÖSER, I. BALASANIAN, F. BANDRABUR

pages 33 - 42
Abstract
In this paper, the study concerning the kinetic of the VOCs oxidation process in the presence of the SCR-DeNOx (0.53% V2O5) commercial catalyst is continued in order to establish the dependence between the temperature and effective kinetics, as well as to assess the apparent activation energy of the reaction. In a previous paper, the experimental data, which allowed the assessment of the reaction order and effective rate constant for the process of benzene catalytic oxidation, in the presence of an excess of oxygen, were presented. It was demonstrated that, at the temperature of 523 K and for space velocities ranged between 2,700...13,100 h-1, the benzene catalytic oxidation in humid air stream (5% vol. H2O) occurs following a first order reaction. For establishing the dependence relationship between the temperature and rate constant, the influence of the temperature upon the benzene catalytic conversion was investigated. The benzene oxidation reaction was carried-out in air stream, both in absence and presence of water vapours (5% vol. H2O), for temperatures ranged between 423...623 K and a space velocity equal to 6,388 h-1. Based on the kinetic analysis it was concluded that the benzene catalytic oxidation process occurs after a combined kinetic mechanism, transport through pores–transformation.

Thermal degradation kinetics of some phosphorus containing aromatic polyesters.

C. HAMCIUC, T. VLAD-BUBULAC, O. PETREUŞ, G. LISĂ

pages 43 - 52
Abstract
Phosphorus containing aromatic polyesters were prepared by polycondensation reactions of 2-(6-oxido-6H- dibenz<c,e><1,2>oxaphosphorin-6-yl)-1,4-riaphthalene diol with different aromatic dicarboxylic acids, such as terephthalic acid, 2-nitroterephthalic acid, isophthalic acid and tert-butylisophthalic acid. The thermal decomposition behavior of the polymers was studied using thermogravimetric analysis in nitrogen, at several heating rates: 10°C/min, 12°C/min and 15°C/min. The polymers showed good thermal stability with decomposition temperature corresponding to 10% weight loss above 345°C. The kinetic processing of data was carried out using Flynn-Wall-Ozawa and Kissinger methods.

Esterification of stearic acid with epichlorohydrin on anion exchange resin catalyst.

E. I. MUREŞAN, S. OPREA, E. HOROBA

pages 53 - 64
Abstract
The effectiveness of different anion exchange resins in esterification reaction of stearic acid with epichlorohydrin was studied. Purolite A-520E resin proved to be the most effective catalyst in the synthesis of 3-chloro-2-hydroxypropyl stearate. The effects of certain parameters such as: speed of agitation, catalyst particle size, catalyst loading, temperature on the rate of reaction, were studied. It was found that the overall rate is intrinsically kinetically controlled. The structures of 3-chloro-2-hydroxypropyl stearate and 2,3-epoxypropyl, stearate obtained by dehydrochlorination of chlorohydrin esters, was confirmed by FTIR analyses.

Microwave - assisted polymerisation applied in synthesis of acryl amide based three-dimensional networks.

C. MIHĂILESCU, V. MUŞAT, V. BULACOVSCHI, G. LISA, B. C. SIMIONESCU

pages 65 - 72
Abstract
Free radical polymerization of acryl amide initiated with potassium oxydisulphate under microwave irradiation was investigated. The polymerization was carried out in presence of formaldehyde, as cross-linking agent, and the effect of monomer and initiator concentration, and formaldehyde/monomer ratio upon conversion was analysed. A significant enhancement of the rates of polymerization was found.

Optimization of mixing in stirred bioreactors. 4. Comparative analysis of the shear promoted by the radial impellers for anaerobic yeasts broths.

E. FOLESCU, A-I. GALACTION, D. CAŞCAVAL

pages 73 - 84
Abstract
With the goal to select the optimum impeller combination for a given broth, the studies on mechanical mixing performances are continued by comparatively analysing the shear forces promoted by seven types of radial impellers on Saccharomyces cerevisiae suspensions of different biomass concentration. The obtained results indicated the following order of the shear stress magnitude, valid for the domain of yeasts concentration of 40...150 g/L d.w.: Disperser sawtooth <<Pitched bladed turbine -- Pumper mixer < Curved bladed turbine << Smith turbine < Paddle with six blades << Rushton turbine. Unlike to the shear rate variation, for each studied impeller the shear stress increases with the increase of S. cerevisiae biomass concentration up to 150 g/L d.w..

The use of PONILIT GT-2 anionic polyelectrolyte as soil conditioning agent.

C. ZAHARIA, I. IVANOV DOSPINESCU, M. MACOVEANU

pages 85 - 92
Abstract
The synthetic PONILIT GT-2 anionic polyelectrolyte can be used as soil conditioning agent for improving the soil ability to support vegetation as grassland, different crops and trees. The increasing values of germination degree for some vegetal species of grass performed when the polyelectrolyte is applied confirm the possibility to remediate the soil fertility into some defavorized sites. The experimental data concludes that the use of low polyelectrolyte concentration increases more than one and half times the germination degrees when is applied together with commercial fertilized soil (e.g.< 25 mg polyelectrolyte/kg soil).

Making functional the white mineral pigments in order to increase the efficiency of the filling the paper process

R. C. CIOCINTA, M.E. CIOBANU

pages 93 - 100
Abstract
The filling is the action of incorporating mineral particles with fine granularity in the fibrous material, in the sheet of paper, respectively. The purpose of this process is to improve paper's optic properties and also other features like the porosity, the smoothness, the printing performance, etc. The experiments of filling the fibers' channels have been accomplished in several variants which included the insertion of calcium carbonate in the celluloid fibers' channels. Therefore, we referred to fibers' treatment with calcium hydroxide solution with a 30% consistency of the paste, and with carbon dioxide, with a low consistency (1.5%, resulting after the treatment with lime cream), with a high consistency, respectively (30%), resulted after elimination of the excess of calcium hydroxide solution. The results are influenced by the paste's consistency as well at the lime cream treatment, as at the carbonate treatment. The only meaningful changes we observed were the decrease of density and the drop of the resistance and, respectively, of the resistance at traction of the paper sheets obtained from the pastes air dried before the lime cream treatment. These changes are obviously due to the breaking up of the structure, because after the drying the fibers weren't milled.

Oxygen delignification of softwood kraft pulps. Some aspects regarding molecular weight of dissolved lignin.

A. C. PUITEL, D. GAVRILESCU

pages 101 - 108
Abstract
The paper deals with some aspects regarding molecular weights (MW) of oxygen delignification (Od) dissolved lignin. The filtrates containing the resulted Od dissolved lignin were obtained in laboratory conditions by oxygen delignification of industrial softwood kraft pulp and subjected to UV-VIS spectrometry analysis and to aqueous gel permeation chromatography on Sephadex G50 and Sepadex LH20 packed columns. The obtained elution curves were used to calculate the molecular mass distributions of the residual lignin present in oxygen delignification filtrates, mostly lignin fragments as suggested by the UV-VIS spectra. It was found that the low molecular fraction (LMW<1,000 Da) increases during oxygen delignification. The lignin contained by the delignification filtrate was precipitated under acidic conditions and subjected to FT-IR spectroscopy. The FT-IR spectral data obtained had little differences, altought pulps with different initial lignin content were used.

Comparative study of environmental impact assessment using the global pollution method applied in the case of four Moldavian solid wastes landfills

C. ZAHARIA, M. SURPATEANU

pages 109 - 124
Abstract
Comparative study of solid waste deposition activities on four different Moldavian landfills was performed using the quantification method of global pollution index in order to assess the environmental impact and to initiate the safe environment-friendly wastes deposition. For this study were necessary different environmental analysis performed for air, water and soil quality during the wastes deposition activities (in the same season of the year). In this paper there were presented the main characteristics of the four studied landfills that corresponded to the conventional deposition process. There were obtained different values of the global pollution index that vary between 1.751 and 3.194 and concluded the fact that the environment was modified by the industrial/economic activities generating discomfort effects to life forms. This fact imposes the necessity of technical and sanitary area ecologization in order to be non- dangereous to life forms.

CRISTOFOR I. SIMIONESCU in memoriam

by V. I. POPA

pages 125 - 126

2006, Issue LII (LVI) , Fasc. 1-2

Studiul spectrofotometric al complecsilor ionilor Fe2+,Co2+, Ni2+ cu 2,2’-dipiridilul

D. BEJAN, AL. DUCA

pages 7 - 20
Abstract
The aim of the present paper is the study of formation of the [ML3]2+ (M2+: Fe2+, Co2+, Ni2+) complexes with 2,2'-Dipyridyl (Dpy). The study was carried out by molecular absorption spectrometry in the visible range, in partially aqueous medium (water-ethanol) with both singular solution of the above mentioned ions and mixed solutions of binary and ternary mixtures. The reciprocal influence of the ions on the spectral characteristics (Amax, λmax, ω) of the [M(Dpy)3]2+ complexes would indicate the possibility of dosing one ion in the presence of the other by means of the calibration curves. The stability constants and molar absorptivities of the [Ni(Dpy)3]2+ and [Co(Dpy)3]2+ complexes were estimated and found to be lower than those for [Fe(Dpy)3]2+. The influence of pH, time and order of reagent addition on the formation and stability of the above mentioned complexes was evaluated. The VIS [M(Dpy)3]2+ spectra were compared to those of the [M(Phen)3]2+ complexes (Phen = 1, 10-phenanthroline) and some similarities and differences connected with structural features of the two ligands were found.

Selective extraction of Hg(II) in aqueous PEG (1550) - (NH4)2SO4 Two - phase system in presence of iodide ions

L. BULGARIU, D. BULGARIU, I. SÂRGHIE

pages 21 - 30
Abstract
The extraction of Hg(II) and of several interfering metal ions (Cd(II), Zn(II), Co(II) and Ni(II)) has been studied in aqueous PEG(1550) - (NH4)2SO4 two-phase system using iodide ions as extracting agents. The distribution studies were carried out at four values of salt stock solution pH, within the pH range between 2 and 7. Unlike of interfering metal ions (Cd(II), Zn(II), Co(II) and Ni(II)), Hg(II) is quantitatively extracted, and the extraction maximum is obtained at lower iodide concentration with high acidity of salt, stock solution. This different extraction behaviour of Hg(II) can be attributed to the formation, in extraction system, of anionic iodide species with high stability. In these conditions,' the Hg(II) selective extraction can be realized in the following cases: a) in extraction systems with a high acidity of salt stock solution (pH = 2.05) and lower concentration of extracting agent (0.02 mol I-/L) or b) in extraction systems with a lower acidity of salt stock solution (pH = 7.12) and high concentration of iodide ions (0.06 mol/L). The values of selectivity coefficients indicate a good separation of Hg(II) towards to these metal ions.

Excess molar volumes of binary mixtures etylbenzene-heptane, octane, nonane, decane and dodecane mixtures at 318.15 K

G. BOLAT, J. ORTEGA, G. LISĂ, I.M. POPA

pages 31 - 38
Abstract
This paper reports the density of ethylbenzene-heptane, octane, nonane, decane and dodecane mixtures at 318.15 K throughout the whole concentration range. The excess molar volumes were calculated from experimental data and fitted to a Redlich-Kister polynomial function and Zeta equation. Results were analysed in terms of molecular interactions.

Considerations concernant la reactivite des elements chimiques du septieme groupe A

S. IFRIM

pages 39 - 44
Abstract
Il est bien connu que dans le groupement des halog6nes la reactivite chimique baisse de fluor very iode, bien que stir la derniere couche electronique - la couche de valence --les atomes des halogenes out, chacun, sept electrons. A.fin d'expliquer la difference de reactivite chimique des elements du septi6ine groupe principal on utilise la notion de densite electronique peripherique, formulee par Pauteur dans tin travail anterieur. Dans le cas des halogenes Fatome de fluor et egalement son ion ont la plus elevee densite electronique peripherique et justement c'est le halog6ne le plus reactif. Cette densite electronique diminue de haut en bas et en meme sens baisse egalement la reactivite chimique des elements de ce groupe principal. Les energies de liaison des balog6nes aver les autres elements comme le hydrogens, le carbon, quelques metaux, sont notablerrient plus elevees dans le cas des fluorures et diminuent graduellenierit dans le cas des autres halogenures. On constate tine diminution parallels de ces energies de liaison aver la diminution des densites electroniques peripheriques des elements correspond ants. A l'aide de cette notion on pent expliquer atissi la variation de quelques caracteristiques des halog6nes, comme: les points de fusion et d'ebullition, la densite ou bien l'enthalpie de hydratation, evidemment prenant en consideration la densite electronique peripherique des molecules et respectivement, des ions des halogenes.

Kinetics of carbon dioxide absorption into ethynendiamine aqueous solution

I. SIMINICEANU, R. TĂTĂRU-FĂRMUŞ, J. M. AMANN

pages 45 - 50
Abstract
The absorption of CO2 into activated carbonate buffer solutions is the main process applied in the existing ammonia plants. The major drawback of this process is the high, endothermicity of the regeneration step. Therefore, new chemical solvents must be introduced having not only high absorption rate and capacity but also low heat of regeneration., The objective of this work was to study the kinetics of CO2 absorption into aqueous solutions of ethylenediamine (EDA). A thermo-regulated constant Pinterfacial area,gas-liquid reactor has been used to measure the carbon dioxide absorption rates into this aqueous amine solution (3% mol) in the temperature range 298...333 K. The experimental results have been interpreted using the equations from the two film model. The enhancement factor was always greater then 3. The pseudo-first order rate constant, derived from the experimental data; was of the same order of magnitude as for absorption into mixtures of inonoethanolamine (NIEA) and N-methyldietanolamine (MDEA).

Modeling the ammonium sulphate solution electro dialysis

I. SIMINICEANU, I.L. COTEŢ

pages 51 - 58
Abstract
A mathematical model was derived to describe the concentration evolution vs. time in a batch-recirculation laboratoryscale electrodialyser. The integrated model contains two constants that have been identified by confronting the computed data with the experimental ones. The relative errors of the model, including the average values of the identified constants, have beet) estimated. The validated model was finally used to extrapolate the electrodialysis (ED) process in order to determine the necessary time for a complete removal of ammonium sulfate, equivalent to a final dilute content of less than 1.5 mol/m3 ammonium sulfate.

Magnetic and ultrasonic cooling water treatment for scale prevention

P. PENA, ST. IVĂŞCANU, O. GEORGESCU, V. IACOB, M. APOSTOLESCU

pages 59 - 66
Abstract
It is widely recognized that the heat transfer is decreasing at the air compression plants due to deposits yielded by the cooling water. Besides the chemical and mechanical conventional methods the literature quotes trials of preventing these phenomena using magnetic and/or ultrasonic methods. The paper presents a case study using a water-air heat exchanging system in an air compression plant to which a, magnetic field and ultrasounds were applied. The heat transfer indexes are computed starting from the equipment's geometry and working conditions. Correspondingly, deposit microstructures in. various working regimes and conditions and the treatment method efficiencies are shown as well.

Influence of the conformational parameters on physical properties of some aromatic poly(1,3,4-oxadiazole-ether)s

C. HAMCIUC, E. HAMCIUC, I. A. RONAVA

pages 67 - 76
Abstract
Conformational rigidity parameters of some aromatic polv(1,3,4-oxadiazole-etlier)s have been calculated by Monte Carlo method with allowance for hindered rotation. Several physical properties such as solubility, glass transition temperature initial decomposition temperature and dielectric constant are discussed in relation with the structure of the polymers and rigidity of their chains.

Multiobjective optimisation of a free radical polymerization process. I. Classical solving methods

S. CURTEANU

pages 77 - 90
Abstract
The optimal control policies for a, polymerization process, particularly for the batch bulk free radical polymerization of methyl methacrylate, have been determined using a multiobjer-tive optimization technique. The process objectives, weightly combined in a scalar function, include minimization of the polydispersity index and the reaction time, maximization of monomer conversion or achievement imposed values for conversion and number average polymerization degree. The decision variables were initial concentration of the initiator and temperature formed by isothermal steps. For solving the optimization problem, a traditional method based on sequential quadratic programming (SQP), implemented in MATIAB, was chosen. Two problems are focussed in the discussion section: the influence of search starting point in the SQP method and the influence of the weights attached to each objective upon the optimization results, in order to find the best values. In a some multlobjective optimization, not the value of the objective function is relevant (even it is a mininium), but the values of the parameters which constitute partial objectives. The solution of the problem represents the result of the user decision which takes into account technological criteria.

Separation of erythromycin by pertraction. Mathematical modelling of facilitated pertraction

D. CAŞCAVAL, A.I. GALACTION, N. NICUTA

pages 91 - 100
Abstract
Using the statistical analysis and a factorial experiment of second order, two mathematical correlations describing the influences of the main parameters (pH-value of feed phase, pH-value of stripping phase, carrier concentration into liquid membrane) on Ery-thromycin facilitated pertraction have been established. The considered variables control the separation process in a 94...98.7% extent, the pH-value of stripping phase exhibiting the most important influence.

Integrating chemistry and biochemistry in papermaking systems

E. BOBU

pages 101 - 118
Abstract
This paper summarizes the results of several years of research concerning the application of the chemical additives and bio-chemicals in papermaking systems that produce corrugating medium from old corrugated containers (OCC) waste paper and are working with a high degree of water circuit closure. First, it is showed that a multi-component retention system consisting of coagulant/ flocculant/microparticies can be an effective way to optimizing the wet end chemistry and. paper quality. At a first sight, such a complex additive system could appears no economical feasible, especially for low paper grades. However a holistic view of the papermaking system allowed us to demonstrate a higher cost effectiveness of the three component additive system comparatively with single or two component systems. In order to minimize the environmental impact of papermaking chemicals, two solutions are investigated: enzymatic treatment of the OCC pulp and application of chitosan, a typical bio-chemical compound, as a substitute of synthetic polymers in the papermaking additive systems. It was showed that xylanase enzyme can enhance papermaking potential of recycled fibers by reducing colloidal dissolved materials and improving the bonding potential of fibers. A comparative study demonstrated that the effectiveness of chitosan as papermaking additive is comparable with that of cationic polyethyleneimine.

Potential toxic elements in the food wrappings. I. Methodology and methods for the determination of organic and inorganic elements

TH. MALUŢAN, N. COTAE, E. POPPEL

pages 119 - 126
Abstract
The paper presents the methodology and methods regarding the determination of toxic organic and inorganic substances that are present in paper and paperboard to come into contact with food wrappers. The obtained data of analysis are in concordance with those obtained in specialized foreign institutes.

GHEORGHE BURLACU in memoriam

by S. IFRIM

pages 127 - 130

BOOK REVIEW:
Polysaccharides - Structural Diversity and Functional Versality, Second Edition, Edited by Severian Dumitriu, University of Sherbrooke, Quebec, Canada

review by V.I. POPA

page 131

2006, Issue LII (LVI), Fasc. 3-4

Co(II) coordination compounds with oxygen organic ligands donor

M. FLONDOR, I. ROŞCA, D. SIBIESCU

pages 7 - 14
Abstract
As a continuation of our previous research, a study of the coordination compounds derived from Co(II) and organic ligands such as: 1-(3,5-dibromo-2-hydroxy-phenyl)-2-phenylsu1fanyl-etharione (L1); 1-(5-bromo-2-hydroxy-4-methylphenyl)-2-phenylsulfanyl-ethanone (L2) and 1-(3,5-dibromo-2-hydroxy-4-methyl-phenyl)-2-phenylsulfanyl-ethanone (L3) are presented in this paper. The used method in this study were: chemical analysis, IR and RES spectroscopy. The experimental data were to assign the structural formulas of the studied compounds.

Synthesis and characterization of the 1,5- pentilen diamin Schiff bases

A. PUI, C. MALUTAN, M. PUI

pages 15 - 20
Abstract
A series of four Schiff bases proceed from derivates of salycilaldehide and 1,5-pentilendiamine were synthesized. These were characterized by elemental analysis, spectroscopie 1H NTNIR, FT IR and UVNIS spectroscopy. The 1H NMR spectra obtained and simulated indicated a very good correlation between chemical shift and intensity of corresponding picks.

Synthesis and biological activities of new 1,2,4-triazole and 1,3,4-thiadiazole derivatives

V. SUNEL, L. PROFIRE, C. MAFTEI, M. POPA, A. CIOBANU, R. JUDELE, A. A. POPA

pages 21 - 30
Abstract
New 1,2,4-triazole and 1,3,4-thiadiazole derivatives were synthesized by intramolecular cyclization of some 1,4-disubstituted thiosemicarbazides in acid or in alkali medium. The chemical structure of the compounds was confirmed by elemental analysis data and IR, 1H-NMR and 13C NMR spectral measurements. The compounds were evaluated in vitro for antibacterial activity against Staphylococcus aureus, Bacillus antracis, Sarcina Luteea, Bacillus cereus, and Escherichia coil. Some of the obtained compounds showed high antibacterial activity against Bacillus antracis and Bacillus cereu. The DL50 values for the synthesized compounds were also established.

Hydrodynamic study of the porous grains fixed bed

I. GALBEN, V. PETRUC, S. PETRESCU

pages 31 - 40
Abstract
An equation to calculate the pressure drop for a fixed bed of porous particles crossed by a gas phase was established. The equation implies the experimental determination of the modified friction factor (Fm) and the establishing of a and n parameters with the equation proposed to calculate the Fm, factor (Fm,= aRe-n). Using spherical silica gel grains (d = 2.57; 3 57 mm), and spherical molecular sieves (d = 2 82; 3.57 mm), respectively, in fixed bed crossed by dried air, pressure drop and a and n parameters, were determined. Based on the values of these parameters there were calculated F, with the relation Fm = f(Re) and the pressure drop with the proposed equation. The agreement between the calculated and experimental values of the pressure drop shows that the proposed equation verifies the experimental data.

Mineralization of crystal violet in water by anodic oxidation, electro-fenton and photo - electro - fenton

I. SIMINICEANU, C.I. ALEXANDRU

pages 41 - 48
Abstract
The paper presents experimental results concerning the Crystal Violet (CV) mineralization in water by three new Advanced Electrochemical Oxidation Processes (AEOPs): Anodic Oxidation (AO), Electro-Fenton (EF), and PhotoElectro-Fenton (PEF).The experiments have been carried out with an open, undivided and thermostated cell with a carbon-PTFE cathode and a BDD anode. All the degradation experiments have been done at pH=3, 308K, 300 mA, and a solution concentration in CV of about 100 ppm total organic carbon (TOC). The EF and PEF treatments were carried out by addition of 1 mM FeSO4 to the starting solution. The mineralization degree has been determined by measuring the residual TOC concentration of the dye in water. The obtained results have shown that the effectiveness of the three methods was increasing as follows: AO<EF<PEF. This relative effectiveness was explained by the specific mechanisms of the hydroxyl radical generation in each process. The influence of small doses of CuSO4 on the effectiveness of EF and PEF has also been investigated. The three new methods investigated proved to be more effective than the TiO2-UV method previously studied by Sahoo and Saquib.

An investigation of the kinetic parameters of the volatile organic compounds oxidation process on SCR-DeNOx commercial catalyst. 1. Evaluation of reaction order and effective constant rate

L. LAZĂR, H. KÖSER, I. BALASANIAN, F. BANDRABUR

pages 49 - 58
Abstract
A study regarding the kinetic aspects of the benzene oxidation process in the presence of the SCR-DeNOx (0.53%wtV205) commercial catalyst was conducted within this paper. Interpretation of the results is done in order to establish the influence of parameters on the equation rate of the benzene oxidation catalytic process. Elimination of the influence of mass transfer through gas phase and study concerning influence of benzene concentration upon conversion allow to establish the catalytic process rate equation. The experimental investigation was carried-out for low concentration of benzene in gas (14...140 ppm) and for a temperature equal to 523 K. For spatial velocities ranged between 2,700 and 13,100 h-1, the rate of the catalytic process is not influenced by reactants mass transfer through gas phase.

p-Cholorobenzoate intercalated in zinc-aluminum layered double hydroxide: a new stable organo-mineral hybrid

A. BOTOMEI, E. DUMITRIU, V. HULEA, A. NASTRO

pages 59 - 66
Abstract
p-Chlorobenzoic acid anion (p-CBA) was intercalated between layers of Zn-Al layered double hydroxides (LDHs). In order to obtain the corresponding hybrid materials three methods of incorporation were applied: direct synthesis by coprecipitation of metal nitrates and sodium p-CBA, ion exchange of the LDH nitrate with organic ion and structure reconstruction of calcined precursor. The solids were characterized by X-ray diffraction, infrared spectroscopy and thermal analyses and the collected data proved the forming of intercalated structures.

Synthesis and characterization of layred double hydroxides intercalated with 2,4-dichlorophenoxyacetic acid

M. FRUNZĂ, M.I. POPA, V. HULEA

pages 67 - 72
Abstract
New organic-inorganic hybrid nanostructures were synthesized by incorporation 2,4-dichlorophenoxyacetic acid (2,4-D) in the layered double hydroxides (LDH). Samples are prepared by using direct co-precipitation of metal nitrates and 2,4-D aqueous solutions. The X-ray diffraction, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric (TG-DTG) analysis point out the presence of the organic compound in the network structure of the samples. Considering together the pesticide family activity of 2,4-dichlorophenoxyacetic acid and the biocompatibility of the layered double hydroxides, the new synthesized materials could open interesting perspectives for obtaining more environmentally friendly insecticides.

Preparation and characterization of a new photocatalyst from synthetic laponite clays

B.-L. IURASCU, I. SIMINICEANU, D. VIONE

pages 73 - 82
Abstract
Photo-assisted Fenton conversion and mineralization of phenol in a 0.1 mM aqueous solution was studied using a new catalyst prepared from synthetic layered clay laponite (Laponite RD) by the pillaring technique. Eight different catalyst samples were prepared: four without thermal aging (WTA), calcined at 523 K, 623 K, 723 K and 823 K, and other four with thermal aging (TA), calcined at the same temperatures. The samples were characterized by XRD and SEM/EDS techniques, and through the bulk chemical analysis. The activity of catalyst samples was evaluated by the phenol conversion (XPh) and phenol mineralization (XTOC) versus reaction time in the presence of 5 mM H202, 1 g/L catalyst, pH = 3, and 303 K. The conversion was almost complete (99.5%) after only 90 s with the TA-623. The highest mineralization (86%) after 90 min was observed with the catalyst TA- 723.

Study of the sulphur dioxide chemosorbtion in slurry of the calcium carbonate residual

AL. SZEP, M. HARJA

pages 83 - 90
Abstract
The paper deals with a study of the reactive dissolution of sulfur dioxide in different natural, synthetic and waste calcium carbonate slurry. Using the modified Lewis reactor it was analysed the influence of nature of carbonate, suspension consistence, milling time, temperature, contact area/volume of reaction mass, overpressure of gases on the kinetic of chemosorption of sulfur dioxide. The IR spectra of the initial, final solids and the crystals formed from mother-liquor indicate the same evolution of process indifferent of the nature of initial carbonate and preparative milling of waste calcium carbonate.

Environmental impact aspects of modern pulp bleaching techniques

A. C. PUITEL, D. GAVRILESCU

pages 91 - 108
Abstract
The environmental impact generated by pulp industry has been analysed in many studies over the last period. The most stringent environmental problems associated with pulp bleaching, one of the most important activity in pulp production, is consume of vi-ater and generation of waste waters. Bleaching with elemental chlorine leads to generation of toxic and refractory chlorinated organics, generally expressed as Adsorbable Organic Halogens (AOX). As consequence to these problems, elemental chlorine bleaching has been replaced by less pollutant techniques as Elementary Chlorine Free (ECF) and Totally Chlorine Free (TCF). The paper reviews the main bleaching stages employed by ECF and TCF, the technological and environmental problems as well as the performances achieved by using ECF and TCF techniques. TCF bleaching by not generating AOX. seems to be the most promising technology even if today it is not as main bleaching technology in pulp industry.

Is a new oil distribution a major risk environmental components

B. ROBU, V. PETRUC, M. MACOVEANU

pages 109 - 116
Abstract
This paper describes a new integrated method for impacts and risks, induced on environment by a new activity related to oil distribution. The new method was developed for main environmental components (surface water, ground water, air and soil), but taking into account the estimated emissions dust and VOCs in air, and the fact that the waste waters are discharged in surface water, for evaluated situation (new activity related to oil distribution) were considered only tow environmental components in assessment process: air and surface water. The new integrated method for environmental impact and risk assessment of new activities or existing activities considers the estimated, respectively measured concentrations of pollutants, and this makes the method to reflect the real situation. Also, the integrated method is based on mathematical steps which loaded to elaboration of a soft designed SAB, and this offers a higher degree of objectivity, and the lack of evaluators doesn't influence the final results. The results of the new method applied to evaluate the environmental impact and risk induced on environment by a new oil distribution station show that a great impact is induced on air, and associated risk is moderate at an unacceptable level. So, the air quality is modified by related activities, and can be dangerous for life forms and this requires actions of pollution prevention and control.

Kinetic study on degradation of Alcian Blui 86x by heterogeneous photocatalysis

A. F. CALIMAN, A. ANTONIADIS, I. PONLIAS, M. MACOVEANU

pages 117 - 128
Abstract
The present paper proposes an investigation of the kinetic of photocatalytic degradation of Alcian Blue 8 GX, a copper phthalocyanine dye, used in biomedical laboratories as stain, in aqueous suspensions containing the commercial catalyst TiO2 P-25.The heterogeneous photocatalytic process was studied for different dye initial concentrations (5...50 mg L-1) and temperatures (293.15 ... 323.15 K). The disappearance of the organic molecule followed approximately a pseudofirst kinetic order according to the Langmuir-Hinshelwood model. The apparent activation energy (Ea), calculated from the Arrhenius' equation, was found to be Ea=19.7 kJ/mol. The small value of activation energy shows that the process of photocatalytic degradation is not very temperature sensitive.

Natural polyphenolic compounds - modulators of yeast fermentation activities

M. DĂNĂILĂ, V. I. POPA, I. VOLF

pages 129 - 136
Abstract
This paper presents a study concerning the biological activity of grape seeds polyphenols in a model experiment of yeast alcoholic fermentation. The observation made is that the polyphenolic products, depending on the concentration used, have a favourable effect on yeast fermentative activity.

TIBERIU GOLGOTIU in memoriam

by I. ROSCA

pages 137 - 139

2005, Issue LI (LV), Fasc. 1-2

Separation of Cd(II) from Zn(II) by extraction in PEG-based aqueous two phases systems in presence of iodide ions

L. BULGARIU, I. SÂRGHIE

pages 7-16
Abstract
The distribution behavior of Cd(II) and Zn(II) has been studied in aqueous two-phase system formed from polyethylenglycol (PEG) and ammonium sulphate, in presence of iodide ions at different pH of inorganic salt stock solution values. The aqueous. two-phase's system are composed of a polymer-rich phase and a salt-rich phase, both which have, an average greater that 70% water content. In absence of iodide ions, both Cd(II) and Zn(II) remained almost exclusively in the salt-rich phase. The addition of I- enhances the metal ions partitioning into PEG-rich phase due to the formation halide complexes. From the distribution ratio, determined as function of iodide concentration, the extracted species were assumed. The extractability of the metal ions is determined by the type of the metal ions complexes, which depends on the pH of salt stock solution. A selective separation of Cd(II) from Zn(II) was accomplished in the aqueous two-phase system by using iodide ions, at high acidity of salt stock solution.

Study on the deviation from ideality of then binary mixtures acetic acid-water, acetic acid-n-hexane and acetic acid-n-heptane

G. BOLAT, G. LISĂ, I.M. POPA

pages 17-24
Abstract
Densities (p) and viscosities (q) for binary mixtures of acetic acid with water, n-hexane and n-heptanes have been measured over the whole composition range at 296.15, 302.15; 308.15; 314.15 and 319.15 K. The excess viscosities were calculated, and the results were used to a Redlich-Kister type polynomial relation. The corresponding parameters have been derived. The resulting excess viscosities were interpreted in terms of the interactions between the molecules in the binary mixture

Synthesis of ferrocene derivatives possesing liquid cristaline properties

I. CÂRLESCU, A.M. SCUTARU, D. APREUTESEI, V. ALUPEI, D. SCUTARU

pages 25-34
Abstract
The preparation of a series of ferrocene containing Schiff bases, possessing liquid crystalline properties, is described. In order to induce mesogenic behavior, the structure of the substituent was systematically varied. Derivatives with no more than two rings in the core exhibit liquid crystalline properties. The synthesized products were characterized using NMR, IR and mass spectroscopy, DSC and polarized optical microscopy.

Benzene oxidation in the presence of halogenated acids on SCR-DeNOx catalysts

L. LAZĂR, H. KOSER, I. BALASANIAN, F. BANDRABUR

pages 35-42
Abstract
Experimentally results achieved from research concerning the benzene oxidation kinetics on commercial SCR-DeNOx, (V2O5-WO3/TiO2, 0.53% wt. V2O5), both in the presence and absence of the halogenated acids (HBr, HCI), in humid air stream (5% vol. H2O) and also in the absence of halogenated acids but in dry air stream, at temperatures of 423...623 K, are presented in this paper. The catalytic conversion of benzene increases with temperature and is negatively influenced by halogenated acids and water vapours. The benzene concentration does not significantly influence the catalytic conversion. Considering the treated gas composition, the apparent activation energy of the benzene catalytic oxidation reaction is ranged between 27...32 W/mol, the oxidation rate being affected by the mass transfer/diffusion process the catalyst level.

Reduction of nitrogen oxides in the presence of hydrocarbons using Sr-Mn-perovskites as catalytic materials

L.M. ABORDEOAIEI, H. PAPP, V. SUPRUN, I. BALASANIAN

pages 43-50
Abstract
In the present work the characterization and the testing of perovskites in SCR-HC were investigated. The perovskites were obtained by Pechini-type method with citric acid and after that characterized by thermo-analytical methods, X-ray diffraction, temperature programmed reduction and BET method. The catalytic activity was tested in SRC-HC equipment using hydrocarbons such as propene and propane as reductants. The results are promising especially for perovskites obtained by calcination at 800°C.

Layered double hydroxides intercalated by phenoxyacetic acid

A. BOTOMEI, E. DUMITRIU, Y.L. PAILLAUD

pages 51-58
Abstract
This paper reports the synthesis of Mg/Al double layered hydroxides (LDHs) by coprecipitation, and of theirs phenoxyacetic acid intercalates by anion exchange, reconstruction and coprecipitation methods. The resulting, LDH, also known as hydrotalcite-like compounds of the type [MII1-xMIIIx(OH)2][Anx/n].mH2O, were characterized by various instrumental techniques, including X-ray diffraction (XRD), IR spectroscopy, thermogravimetric analysis (TG) and chemical analysis. According to the XRD technique the phenoxyacetic acid is better intercalated by coprecipitation method than anion exchange.

Introduction of Aluminium into MCM-22 zeolite structure by two different methods hydrothermal synthesis and isomorphic substitution

O.A.RUSU, A.S. MASSERON, E. DUMITRIU

pages 59-70
Abstract
Deboronating the zeolitic structure of ERB-1 and then, by hydrothermal treatment in the presence of corresponding precursors, new metallic cations, especially transition metals, call be inserted in the vacant tetrahedral framework positions. Thus, isomorphically substituted MCM-22 zeolites, obviously materials that are difficult or impossible to be synthesized by direct hydrothermal synthesis, call be obtained. In the present work we have successfully used this procedure to insert aluminium in the framework of deboronated ERB-1 in view to obtain high-silica Al-MCM-22, material difficult to be prepared by a direct hydrothermal synthesis.

A comparative study on the native volcanic tuff and its Na from in the exchange process with some heavy metal ions

Cl. COBZARU, C. CIBOTARU, S. OPREA, V. HULEA

pages 71-78
Abstract
The native volcanic tuff and that modified with sodium were used for retaining some metallic ions (Cr3+, Fe3+, Cd2+, Ni2+ and Pb2+) from aqueous solutions. The tuff modified with sodium ions was found to be much more efficient that the native one for all the metallic ions used in the exchange process.

The effect of oxygen-vectors on vitamin B12 biosynthesis

E. FOLESCU, A.I. GALACTION, A.C. BLAGA, D. CAŞCAVAL

pages 79-88
Abstract
The addition of n-dodecane in culture of Propionibacterium shermanii, the main producer of vitamin B12, leads to the considerable increase of oxygen transfer rate from air to fermentation broth. The experiments indicated the existence of a certain value of hydrocarbon concentration that corresponds to maximum mass transfer rate of oxygen. The magnitude of the positive effect of oxygen-vector strongly depends on operational conditions of bioreactor, on broths characteristics and on Propionibacterium shermanii concentration.

Bilirubin metabolism at fetus and newborn

C. ANTON, D. BOLDUREANU

pages 89-94
Abstract
Knowledge of the bilirubin metabolic stages is an important step for the newborn jaundice prevention. Jaundice is the most common and one of the most vexing problems that can occur in the newborn. Although most jaundiced infants are otherwise perfectly healthy, they make neonatologist anxious because bilirubin is potentially toxic, to the central nervous system.

Phototherapy in RDH isoimmune hemolysis

C. ANTON, D. BOLDUREANU

pages 95-104
Abstract
The RbD isoinimunization (anti-D) is a current problem for neonatal assistance. Kernicterus represents an important complication, sometimes even lethal, because of the rise of indirect bilirubin. This study had the objective to identify the newborn with RhD (anti-D) isoinimunization, the diagnosis and the therapeutically procedures applied in order to prevent hyperbilirubin encephalopathy.

Ecological footprint - an instrument of sustainable development

D.M. ILIE, N. PEIU, M. GAVRILESCU

pages 105-112
Abstract
A few years ago, a, new concept was for the first time used in environmental assessment. The term in question was "ecological footprint", a new method for evaluating the impacts of a human society of consumption on the environment. The original method, created by Wackernagel and Rees, uses six types of areas in order to calculate the ecological footprint of a society, usually for a country or region, but also for the entire human society, at global level. The result, of this evaluation is presented as an only figure number and can be used, to compare different countries with different land and water supplies and different populations, in order to asses the contribution of each country to the global footprint. The purpose of the present paper is to asses Romania's ecological footprint for three consecutive years (1999,..., 2001). The data used for this paper were taken from the official annual statistics of the state of Romania, from the Food and Agricultural Organization and other bibliographical sources. The obtained results have been compared with those of the World Wild Found for Nature, the single international organism which evaluates periodically the ecological footprint of all Earth's nations.

Qualitative and quantitative analysis of romanian propolis samples from different geographical areas

C. LUCA, S. ANDREI, M. PANAIT, M. POPESCU

pages 113-120
Abstract
Results of a preliminary study regarding the chemical composition of propolis performed by the investigation of qualitative and quantitative parameters are presented. The evaluation of propolis quality was made by using propolis samples prelevated from different Romanian geographical areas.

Studies regarding the sorption-desorption processes of permetrine solutions in various wood essences used as support for cultural patrimony goods

V. VASILACHE, C. LUCA, I. SANDU, A.I. SANDU

pages 121-126
Abstract
A comparison between the sorption/desorption curves of permetrine solution for four samples of new wood and four samples of old wood affected by death watch found in a precarious state of conservation, from the structure of the support or frame of a wood icon is performed.

2005, Issue LI (LIV) , Fasc. 3-4

Refractive indices and molar volumes of binary mixtures n-propanol-water and n-propanol-toluene

C. LISĂ, G. LISĂ

pages 7 - 14
Abstract
This paper is aimed to determine the refractive indices of n-propanol-water and n-propanol-toluene solutions, in a wide composition range, at various temperatures and atmospheric pressure. Based on these experimental data, we calculated the excess refractive indices and we estimated the excess molar volume of the studied systems. The obtained results were compared with the values of the excess molar volume of previous studies concerning the density of these binary mixtures.

Corrosion behavior of some dental alloys

D. MARECI, D.M. AELENEI, GH. NEMŢOI, N. AELENEI, C. BOCANU

pages 15 - 22
Abstract
The corrosion behavior of pure titanium, four titanium alloys and four Ni-Cr and Co-Cr dental alloys in a Ringer type solution was studied by potentiodynamic method. The main parameters of corrosion process were determined from linear and cyclic polarization curves. The most resistant to corrosion seem to be titanium alloys while the dental alloys containing Fe or Cu show pitting type corrosion. The keeping for 24 h of these alloys in Ringer solution leads to a relative passivation, excepting the alloys which present pitting corrosion.

Coordinative compounds of Ni(II) with tetra-chloro salen and tetra-chloro salophen types ligands

A. PUI, C. MĂLUŢAN

pages 23 - 30
Abstract
The Schiff bases with two chlore atoms graphed on the salicyl-aldehyde or salicylketone molecule and with -H, -CH3 or CH3-CH2- in the imminic-position was synthesized as ligands. The chain between N-N atoms donors is ethylene or phenylene. The Ni(II) forms with such ligands complexes with square planar or nearly planar geometry. The ligands and the complexes were characterized by elemental analysis, UV-VIS, FT-IR and NMR spectroscopy.

Electrodialysis of ammonium sulfate solutions. II.Conductivity measurement and correlation

I. SIMINICEANU, L.I. COTEŢ

pages 31 - 36
Abstract
The paper deals with the conductivity measurement of ammonium sulfate solutions

Mass transfer with chemical reaction in single drops

S. PETRESCU, F. UNGUREANU

pages 37 - 44

Mathematical modeling of folic acid separation by reactive extraction

A.I. GALACTION, A.C. BLAGA, D. CAŞCAVAL, E. FOLESCU

pages 45 - 52
Abstract
Using the statistical analysis and a factorial experiment of second order, a mathematical correlation between the folic acid reactive extraction degree and the main parameters influencing the process (Amberlite LA-2 concentration, pHvalue, duration) have been established. The considered variables control the extraction process in a 95.2% extent, the pH-value and the extractant concentration in organic phase exhibiting the most important influences.

Kinetic study of vitamin C reactive extraction with Amberlite LA-2

A.C. BLAGA, A.I. GALACTION, D. CAŞCAVAL

pages 53 - 58
Abstract
The separation of vitamin C by reactive extraction with Amberlite LA-2 dissolved in dichloroiriethane represents an advantageous alternative to the downstream processes applied at industrial scale. The reactive extraction occurs by interfacial formation of an ammonium salt solvated by extractant molecules. The corresponding interfacial equilibrium suggested a chemical reaction of second order between the solute and the extractant. The corresponding values of interfacial reaction rates and constant have been calculated. The results indicated that the value of velocity constant is k2 = 4.884 ·10-4 L/mole.s, greater than the values obtained for others vitamins extraction with Amberlite LA-2.

Liquid crystal maleimide monomers

C. HULUBEI, D. BUICEAC

pages 59 - 66
Abstract
Two new maleimide monomers containing azomethine, amide and azo groups were synthesized and structurally characterized. The new maleimides have been synthesized by solution polycondensation reaction from the p-aminoazobenzene with N-(4-formyl-phenoxy-4'-carbonylphenyl) maleimide and 4-maleimido-benzoyl chloride, respectively. The monomers were characterized by elemental analysis and infrared and proton nuclear magnetic resonance spectroscopy. The liquid crystal behavior of these compounds was characterized by differential scanning calorimetry (DSC) and hot-stage polarized light microscopy (PLM). The both maleimides exhibited thermotropic liquid crystalline behavior.

Controlled water delivery systems for dried soils. I. Copolymer synthesis and water delivery mechanism

T. RUSU, V. BULACOVSCHI

pages 67 - 76
Abstract
The possibility of using copolymer systems for improving soil humidity in dry atmospleric conditions is proposed. The investigation was made in case of different amphiphilic copolymers, but this paper presents only the synthesis and characterization of the copolymer networks made up from poly (dimethylsiloxane) (PDMS) and poly(methacrilic acid) (PMAA) sequences. Also, the networks were investigated as controlled water delivery systems in dry soils, being proposed a possible mechanism.

Surface characterisation of free-radical mass polymerization obtained acrylic copolymers for artificials crystalline implants

C. LOSPA, M. RUSU, M. VONE, M.H. ADAO, P. SUCKLING, J. DE CONINK

pages 77 - 82
Abstract
The results of a study regarding surface properties of a series of acrylic copolymers obtained by free-radical mass copolymerization are presented. The study is part of a research project on polymeric biomaterials with potential use for a crystalline lens implant to restore accommodation. The following monomers were used to obtain acrylic copolymers: metyl metacrylate, cyclohexyl metacrylate, 2ethyl hexyl acrylate, butyl acrylate. The critical surface tension and wettability of these copolymers were investigated through measurements of the static contact angle, using water, alkanes and ethanol/water mixtures as liquids.

Properties of conductive fibres based on polyaniline

L.R. MANEA, A. NECHITA

pages 83 - 88
Abstract
The conductive fibers obtained by chemical coating are studied. Different conductive materials have been used in order to obtain conductive pol-yethylene terephtalate and Dyneema-based fibres with specific electrical and mechanical properties. The electric conductivity of these fibres have been investigated and the obtained results are discussed. These fibres are intended for use in creating conductive yarns and realizing connections In smart clothing or producing conductive fabrics which can be used as electromagnetic shields.

Cellulose dissolution in lithium chloride/N,N-dimethylacetamide system under microwave irradiation

C. MOCANU, S. CIOVICĂ, A. MURARIU, K. PIELICHOWSCHI

pages 89 - 98
Abstract
The importance of cellulose dissolution in lithium chloride (LiCl)-N,N-dimethylacetamide (DMAc) system is presented. The mechanism of dissolution is not very well understood even after two decades of use. There are some models which try to explain the interaction between LiCI-DMAc and cellulose. The efficiency of the system is associated with lower degradation rate. A new method for cellulose dissolution by classical activation combined with microwave irradiation is proposed.

Sources of solid wastes in pulp mills.

D. GAVRILESCU

pages 99 - 106
Abstract
The pulp mills generate various quantities of solid wastes, depending on technological level, pulp grade and wood quality. These wastes are generated in all stages of pulp manufacturing: wood processing, pulping, pulp washing and screening, chemicals recovery. The minimizing of solid waste generation and the ways of their processing are important problems for the pulp producers. These problems are in strong connection with both the economical and environmental aspects. Aims of this paper are to identify the sources of solid wastes in the kraft (sulfate) pulp mills and to discuss the best ways of their processing. The wood room represents the major area of wood wastes that are very different regarding their shapes, dimensions and properties. Bark is the most common wood waste and its volume ranged between 0.4...0.6 m3 /t o.d. pulp. Besides bark, other wood residues appear in the wood room: fines, pins, large chips. Their quantities are very different depending on the wood quality, debarking method, and chipper performance. The most common way for their valorization is by firing for energy using fluidized bed furnace boiler. Wood-waste burning allows to obtain 0.8...1.2 t steam (1.2 MPa)/t of o.d. pulp, depending of the wood losses at pulpwood preparation. Another source of solid waste is the pulp screening stage where results 2...8% knots and fine-screen rejects. The third major source of solid wastes in the kraft pulp mill is the recovery plant, generating sodium salts enriched with NaCI and KCI from recovery boiler, dregs from green liquor clarifier/filter, and grit separated at slaker. Land filling is the only way of dregs and grit disposal. Waste materials for landfill consist of ash, dregs and grit. A good waste management in pulp manufacturing leads to enhancing of economical performance as well as to an environmental sound process.

Environment impact and quality control on an old moldavian municipal wastes landfill

C. ZAHARIA, M. SURPĂŢEANU

pages 107 - 120
Abstract
Over more than 30 years, the deposition of municipal wastes was usually done on special landfill that influenced negatively the environment quality. To express the pollution level into the area of deposition and proximity, an environmental impact assessment is always necessary based on the environment analysis performed for air, water and soil quality during the whole waste deposition activities. In this paper, there are discussed the principal aspects of municipal waste deposition conventional process on an old Moldavian landfill and, also, the environment impact of the technological deposition process. The environment quality data were obtained by standard analysis methods of the quality indicators methods internationally approved (ISO). The environmental impact of wastes deposition is assessed using the well known method of global pollution index.

On the behavior of natural polyphenolic products as plant growth regulators

A. BALAŞ, M. DĂNĂILĂ, V.I. POPA, N. ANGHEL

pages 121 - 126
Abstract
This paper presents a study concerning the biological activity of spruce bark polyphenols in a model experiment of tomato seeds germination and plant cultivation. The observation made is that the polyphenolic products have a favourable effect, depending on the concentration used. Also, it was obvious a similar action to that of the plant growth hormones, especially to auxines and citokinins.

Activated carbon adsorption for the treatment of the pulp and paper industrial wastewater

D. TELEMAN, C. TEODOSIU, F. UNGUREANU, I. BALASANIAN

pages 127 - 134
Abstract
This paper presents the results of a study concerning the removal of phenolic compounds from wastewater resulted from pulp and paper industry on granular activated carbon (GAC) PUROLITE AC 20G previously thermally regenerated. The wastewater was formerly filtered and the physical and chemical indicators were determined. The spectrophotometric method with p-nitroaniline without extraction was used to establish the phenol concentrations. The influence of the operating parameters was studied in terms of: flow (Q), contact time between the adsorbent and wastewater (t,) and the height of the activated carbon bed (H,). The best results concerning the removal efficiencies were obtained by decreasing the values of the flow at increased values of the height of the activated carbon bed. An efficiency of phenol removal of 67% was obtained at Q = 5 ml/min and for H, = 4 cm. Phenol concentrations in the effluent after 24 h of process interruption had decreased (as compared to those in the interruption moment) due to the fact that microorganisms from wastewater consume part of the organic compounds adsorbed at the GAC surface and thus GAC recovers partially its adsorption capacity. A comparative study regarding the phenol adsorption efficiency from synthetic solutions containing phenol on new and regenerated granular activated carbon was performed. By correlating the variation of phenol removal efficiencies depending on flow and time for all the results achieved, the mathematical model of the process using the Table Curve 3D software was achieved.

2004, Issue L (LIV), Fasc. 1-2 (June)

Kinetic study of the reactive dissolution of marble into sulphur dioxide solution

AL. SZEP, GH. MIHĂILĂ, S. BARTHA, N. CAŞU

Corrosion tendency evaluation by electrochemical methods for some dental alloys in simulated salivas

D. AELENEI, D. MARECI, GH. NEMŢOI, N. AELENEI

Aromatic polyamides containing acetoxybenzamide pendent groups

I. SAVA

Modified polymers based on PAV designed for stabilization and protection of patrimony objects

M. NĂNESCU, M. IVĂNOIU, V. BULACOVSCHI

Spectrometric variants for determination of the tannins in wines

D. BEJAN, L. BULGARIU, G. RUSU

Structural analysis of Vanadium mixed oxides derived from substituted hydrotalcite studied

G. CÂRJĂ, M. IRIMIA

Mathematical modelling of volcanic tuff behaviour in ion exchange process. Ion exchange with Cr3+ and Fe3+

Cl. COBZARU, S. OPREA

Functional polymers based on salicylic acid derivatives

C. HULUBEI, C.D. VLAD

Content of some proteic preparates by ion exchange chromatography with gradient elution

D. BEJAN

Salt air generator for medicine recovery and environmental sanitation

G. CIOBANU et. al.

Pollution prevention in large volume organic chemical industry

C. MUŞAT, M. GAVRILESCU

Overview on integrated pollution prevention and control for the tanning of hides and skins sector

O.M. TIMOFTE, M. GAVRILESCU

2004, Issue L (LIV), Fasc. 3-4 (December)

Atom transfer radical polymerization. 1. Investigation of the catalytic system based on Cu(0) and 2,2’-bipyridyl

E. TĂRAN, M. LĂZĂRESCU, B. DONOSE, I. CÂRLESCU, N. HURDUC

The evaluation of rheological characteristics for some better types controlled-stress rheometry

V. MAIER, S. MAIER, M. COLŢ, V. BULACOVSCHI

Development of the mathematical model of the volcanic tuff behaviour in the ionic exchange process. Ion exchange with Pb2+, Ni2+ and Cd2+

Cl. COBZARU, S. OPREA

Contributions to the mechanism of the thermal decomposition reaction on the ammonia

D. DÂRŢU, L. ODOCHIAN, M. DUMITRAŞ

Neural network based modelling for viscosity of some binary systems

S. CURTEANU, G. LISĂ

Preparation and characterization of bismaleimide-diphenol prepolymers

C. HULUBEI I. FECHETE, P. CAULLET, E. DUMITRIU, V. HULEA, H. KESSLER

Catalytic activity of the Al-EMT and AlGa-EMT zeolite. Study of gas-solid heat transfer accompanied by solid phase change

S. PETRESCU, A, FRUNZĂ, M. SECULA

Powder coatings-based organic films

M. RUSU, C.E. MOCANU

Rheological study of film forming mixtures

V. MAIER, S. MAIER, V. BULACOVSCHI, V. BUCEVSCHI

Adhesive compositions based on vinylacetate-acrylic copolymers

C. MIHĂILESCU, M. DĂRÂNGĂ, V. BULACOVSCHI

Study of mass transfer in anodic dissolution process

M. SECULA, I. CREŢESCU, S. PETRESCU