Modeling of Noncatalytic Gas-Solid Reactions the Reaction Zone Thickness
EUGENIA TEODORA IACOB-TUDOSE, “Gheorghe Asachi” Technical University of
Iasi, „Cristofor Simionescu” Faculty of Chemical Engineering and
Environmental Protection,
etudose@ch.tuiasi.ro
Abstract A number of physical and mathematical models have been
proposed for noncatalytic solid-gas reactions. In such a system, the
reaction takes place in a part of the solid that can vary in large limits.
Within this study, calculations with respect to the gaseous reactant, for
simple isothermal first order reactions, have been carried out. The size of
the specific reaction area is established and correlated with a mathematical
model characterizing the chemical transformation that takes place. Depending
on the specific thickness of the reaction zone, some well-known noncatalytic
gas-solid reaction models such as: the shrinking core model (heterogeneous),
the limited reaction zone model (general) and the total reaction zone model
(homogeneous), have been re-established. Keywords: gas-solid reaction
models, specific thickness of the reaction zone, rectangular coordinates,
spherical coordinates
Spectrophotometric Determination of Rifampicin in Aqueous Solution
IUSTINA-DENISA TANASĂ, “Gheorghe Asachi” Technical University of Iaşi,
“Cristofor Simionescu” Faculty of Chemical Engineering and Environment
Protection ANDREI-EUGEN BULGARIU, Emergency Hospital Professor Doctor
Nicolae Oblu of Iaşi, Romania CĂTĂLINA SIRIŢEANU, “Gheorghe Asachi”
Technical University of Iaşi, “Cristofor Simionescu” Faculty of Chemical
Engineering and Environment Protection LAURA BULGARIU, “Gheorghe Asachi”
Technical University of Iaşi, “Cristofor Simionescu” Faculty of Chemical
Engineering and Environment Protection,
lbulg@ch.tuiasi.ro
Abstract In this study, a simple spectrophotometric method was
developed for the quantitative determination of rifampicin in aqueous
solution. The method is based on the property of rifampicin to modify, in
aqueous media at pH of 7.0, the degree of ionization of the functional
groups. After ionization, a coloured compound is formed, which can be
analysed spectrophotometrically. The visible spectra of the yellow compound
were recorded at pH of 7.0, in different buffer solutions (phosphate,
hexamethylentetraamine (HMT) and borax) and the qualitative characteristics
were determined. The highest absorbance was obtained in phosphate buffer, at
λ = 470 nm, against distilled water, and these conditions were selected for
quantitative determinations. This procedure allows the quantitative analysis
of rifampicin in a wide concentration range (0.01 - 0.16 mmol·L-1), with a
detection limit of 0.0002 mmol·L-1. The very good correspondence between the
calculated and experimental values of rifampicin concentration shows that
this method is valid and can be used for quantitative analysis, at least for
laboratory studies. Keywords: spectrophotometric method, rifampicin,
quantitative determination, aqueous solution.
Surface Modification Induced by Aqeous Environment of
Nucleobase-Modified Azo-Polysiloxanic Films
CRISTINA-MARIA HERGHILIGIU, “Gheorghe Asachi” Technical University of
Iași, “Cristofor Simionescu” Faculty of Chemical Engineering and
Environmental Protection,
cristina-maria.herghiligiu@academic.tuiasi.ro NICOLAE HURDUC, “Gheorghe Asachi” Technical University of Iași, “Cristofor
Simionescu” Faculty of Chemical Engineering and Environmental Protection
Abstract Taking into account the use of nucleobase-modified
azo-polysiloxanic films as supports for cell cultures but also for the
immobilization of biomolecules application (especially DNA, RNA) which
involves contact with the aqueous environment, a study of the surface
properties of these compounds was carried out by evaluating the contact
angle of dry and wet surface of the samples. This study was completed and
correlated with AFM behavioural studies of surfaces under aqueous media. The
studied samples show a dynamic surface that can be controlled,
reorganization of the polymer chains taking place depending on the chemical
structure. Keywords: contact angle, nucleobases, AFM, azo-polysiloxanes,
aqueous environment.
Preliminary Study on the Interaction of Skin Microbes in the Development
of Cosmetic and Textile Products: A Review
ABDOURAMANE NSANGOU, Department of Mechanical Engineering, ENSET,
University of Douala, BP 1872, Douala, Cameroon DOINA SIBIESCU, “Gheorghe
Asachi” Technical University of Iaşi, “Cristofor Simionescu” Faculty of
Chemical Engineering and Environmental Protection, Iaşi, Romania,
dsibiesc@tuiasi.ro DYDIMUS NKEMAJA EFEZE, HTTTC Bambili-University of
Bamenda, Cameroon PIERRE MARCEL ANICET NOAH, Department of Mechanical
Engineering, ENSET, University of Douala, BP 1872, Douala, Cameroon FABIEN EBANDA BETENE, Department of Mechanical Engineering, ENSET,
University of Douala, BP 1872, Douala, Cameroon VALERY HAMBATÉ GOMDJÉ,
Departments of Textile and Leather Engineering, ENSPM, University of Maroua,
Cameroon
Abstract This work, which aims at realizing a synthesis of the
knowledge on cutaneous microbes, shows that the skin is made up of
pathogenic microbes and commensal microbes. The resident or commensal
microbes are defenders of the skin and are ready to compete for nutrients
and available space. Therefore, pathogenic microorganisms will not be able
to settle and grow. The textile designer, in his search for an antimicrobial
textile, should not be satisfied with the ability to inhibit skin microbes.
He should investigate whether his textile promotes the balance of the
commensal flora before testing the inhibition of the transient flora. For
this reason, it is desirable to know the skin flora before embarking on the
implementation of antimicrobial textiles. Keywords: textiles,
antimicrobial, pathogenic microbes, commensal microbes
Sustainable Management, Treatment and Recovery of Waste in an European
Context: Urban Mining and the Circular Economy
MIHAELA DAVID, “Gheorghe Asachi” Technical University of Iasi,
“Cristofor Simionescu” Faculty of Chemical Engineering and Environmental
Protection, Iasi, Romania MARIA GAVRILESCU, “Gheorghe Asachi” Technical
University of Iasi, “Cristofor Simionescu” Faculty of Chemical Engineering
and Environmental Protection, Iasi, Romania, Academy of Romanian Scientists,
Bucharest, Romania, mgav@tuiasi.ro
Abstract The paper provides an overview of waste management
alternatives in the European framework of the circular economy model, with
emphasis on the use of waste as secondary sources for the recovery of raw
materials and materials, especially critical raw materials and highlighting
the importance of economic and environmental impact of this approach. In
this context, the following were taken into account: analysis of European
urban waste management practices; highlighting the relevance of waste
recovery in the context of the circular economy; recovery of critical raw
materials (CRM) from specific waste, as secondary sources of raw materials.
In the last part of the paper, a series of methods for the recovery of
secondary and critical raw materials from waste were highlighted, analyzing
the case of recovery of cobalt from secondary resources, such as waste
lithium batteries, as important for lithium and a few other critical
materials, as well. Keywords: critical raw materials, recovery,
recycling, secondary resources, waste.
An Overview on Phytoremediation as a Promising Technology for
Environmental Depollution
RALUCA-MARIA ȚÂBULEAC, “Gheorghe Asachi” Technical University of Iasi,
“Cristofor Simionescu” Faculty of Chemical Engineering and Environmental
Protection, Iasi, Romania MARIA GAVRILESCU, “Gheorghe Asachi” Technical
University of Iasi, “Cristofor Simionescu” Faculty of Chemical Engineering
and Environmental Protection, Iasi, Romania, Academy of Romanian Scientists,
Bucharest, Romania, mgav@tuiasi.ro
Abstract The paper develops a succinct analysis of the
phytoremediation process of soils polluted with heavy metals. A number of
basic aspects regarding the pollution of soils with heavy metals and the
consequences of this phenomenon are presented. Also, the mechanisms by which
some plants absorb heavy metal ions are described, a series of studies are
presented in which different categories of plants were used as
hyperaccumulators to remove heavy metals from the soil and possibilities to
intensify phytoremediation. Based on information from the literature, the
removal of heavy metal ions (or associated with this group of chemical
elements) from the soil, such as cadmium, arsenic, mercury, selenium was
explored. The analysis presented in the paper could support and justify the
application of phytoremediation as an alternative for environmental
remediation in friendly conditions, with low costs and without additional
negative impacts on the environment. Keywords: Brassicaceae, heavy
metals, hyperaccumulator, rhizosphere, soil.
Natural carriers for bacterial immobilization used in bioremediation
EMANUEL GHEORGHIȚĂ ARMANU, “Gheorghe Asachi” Technical University of
Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering and
Environmental Protection, Iaşi, Romania IRINA VOLF, “Gheorghe Asachi”
Technical University of Iaşi, “Cristofor Simionescu” Faculty of Chemical
Engineering and Environmental Protection, Iaşi, Romania,
iwolf@tuiasi.ro
Abstract In the last few decades, the environment has been
drastically polluted due to the fast industrialization and other anthropic
activities. As a boomerang effect, different areas around the world started
to shift their original state to one where life itself is continuously
diminished, mostly resulting from hazardous circumstances. Microorganisms,
in particular bacterial strains have a key role in the bioremediation
process due to their efficiency, friendly-environment effect and cheap cost
of use. Bioremediation started traditionally using just free cells as a
decontaminating tool, however, in couple of years, immobilized
microorganisms gained a lot of attention due to their higher stability,
retention in time and biotransformation efficiency. Aforementioned
immobilization can be realized either on natural or synthetic carriers. The
main goal of this paper is to summarize and bring in the spotlight some
relevant data regarding the microbial immobilization on specific natural
carriers (derived from biomass conversion) and its importance for
environmental remediation. Keywords: feedstock, porous materials,
persistent organic pollutants, microbial biofilm, bioremediation.
Crystal Violet Dye Adsorption on Raspberry Leaves Powder - Kinetic and
Thermodynamic Studies
GIANNIN MOSOARCA, Faculty of Industrial Chemistry and Environmental
Engineering, Politehnica University Timisoara, Romania,
giannin.mosoarca@upt.ro COSMIN VANCEA,
Faculty of Industrial Chemistry and Environmental Engineering, Politehnica
University Timisoara, Romania SIMONA POPA, Faculty of Industrial
Chemistry and Environmental Engineering, Politehnica University Timisoara,
Romania SORINA BORAN, Faculty of Industrial Chemistry and Environmental
Engineering, Politehnica University Timisoara, Romania MARIA ELENA
RADULESCU‑GRAD, “Coriolan Dragulescu” Institute of Chemistry, Romanian
Academy, Timisoara, Romania
Abstract In this study, kinetics and thermodynamics of crystal
violet dye adsorption onto raspberry leaves powder was investigated. The
effect of contact time, temperature and ionic strength was studied. The
values of the equilibrium time and the experimental adsorption capacity were
better that values for other similar adsorbents obtained from vegetal
wastes. The thermodynamic study showed that the adsorption process is
endothermic, spontaneous and favourable, and physical adsorption is the main
mechanism implied in the dye retention on the adsorbent surface.
Keywords: adsorption, crystal violet, raspberry leaves, contact time,
thermodynamic parameters.