2016, Volume 62(66), Issue 2 (June)

Contents

pages 1- 8    Download

Spectrophotometric Determination of Cu(II), Co(II) and Ni(II) Ions in Mono and Multi-Component Systems

VLADISLAV FORNEA, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection
ŞTEFAN TRUPINĂ,
 "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection
ALEXANDRU VASILICĂ IOSUB,
  "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection
LAURA BULGARIU,
 "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection, lbulg@ch.tuiasi.ro

pages 9 - 20    Download
Abstract
The selective determination of Cu(II), Co(II) and Ni(II) ions from aqueous solution was spectrophotmetrically investigated using rubeanic acid as color reagent. The reaction between Cu(II), Co(II) and Ni(II) ions with rubeanic acid occurs rapidly at pH 3.5 in case of Cu(II) ions and at pH 9.0 in case of Co(II) and Ni(II) ions (buffered solutions). The metal complexes have absorption maximums at different wavelength (380 nm for Cu(II), 480 nm for Co(II) and 590 nm for Ni(II), respectively) and this characteristic underlies the possibility of their determination in multi-components systems. This method allows the determination of these metal ions in a relatively wide concentration range, with acceptable detection limits. The interferences caused by each metal ion in the determination of the other were evaluated on the basis of  the selectivity coefficients. The validation of Cu(II), Co(II)  and  Ni(II) determination through this method was done by recovery tests of metal ions in tap water. The obtained results shows that this spectrophotometric method can  be successfully used for the analysis of Cu(II), Co(II) and Ni(II) ions in water samples, whether are in mono- or multi-components systems.
Keywords: metal ions; rubeanic acid; aqueous solution; spectrophotometric method.

Determination of Mineral Acids Concentration from Mixtures by Condutometric Titration

MONICA-MARIA ROMAN, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection
IONELA CIURDEA,
"Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection
CRISTINA LAZAREV,
"Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection
LAURA BULGARIU,
"Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection, lbulg@ch.tuiasi.ro

pages 21 - 31    Download
Abstract
In this study, a conductometric titration method is proposed for the quantitative determination of two mineral acids (HCl and H3PO4), both individually and from mixture. Conductometric titration assumes the experimental measuring of electrical conductivity of the analyzed solution as a function of added titrant volume, and depends by the concentration of all ions present in this solution. A solution of AgNO3 (0.1 N) was used as titrant. Both mineral acids react with AgNO3 and form low soluble compounds (AgCl and Ag2HPO4), and these reactions are the basis of their determination by conductometric titration. If, HCl can be analyzed in this way with  high  accuracy, regardless of whether is in mixture or not, the  determination  of  H3PO4 acid is more difficult due to the high solubility of Ag2HPO4 precipitate. Thus, the neutralization of H3PO4 acid with NaOH (0.1 N) solution before to start the conductometric measurements is necessary, for that his quantitative determination to be possible. Therefore, the conductometric titration with  AgNO3 can be used for the determination of HCl and H3PO4, both individually and from mixtures, but this is possible only after neutralization of the mineral acids with a strong base solution.
Keywords: mineral acids; mixtures; condutometric titration; AgNO3 titrant; aqueous solution.

Analytical Methods for Analyzing Some Oils Used in Cosmetics

GABRIELA GAVRILUȚĂ, Secondary School "I. Teodoreanu" Iaşi, gavriluta.gabi@yahoo.com

pages 33 - 38    Download
Abstract
In this paper three different oils have been analysed: sesame, olive and jasmine. For their analyses standard methods for oils and  fats described by American Oil Chemists Society (AOCS,  1993)  and  pharmacopoeia assays (Brazilian pharmacopoeia, 2010), such: index of acid, saponification, iodine, peroxides, determination of potential of hydrogen (pH), and density. Those analyses are important because they indicate the quality and authenticity of the oil. The results showed that the oil extracted from sesame and olive has acceptable characteristics and is of good quality. For all of those the saponification index, the acidity and peroxidation value have been determined.
Keywords: index of acid; index of saponification; index of peroxide; olive; jasmine; sesame oils.

 Third Generation Biotehanol Production

ALEXANDRA CRISTINA BLAGA, "Gheorghe Asachi" Technical University of Iași, Faculty of Chemical Engineering and Environmental Protection
LENUȚA KLOETZER,
"Gheorghe Asachi" Technical University of Iași, Faculty of Chemical Engineering and Environmental Protection
ALEXANDRA TUCALIUC,
"Gheorghe Asachi" Technical University of Iași, Faculty of Chemical Engineering and Environmental Protection
DAN CAȘCAVAL,
"Gheorghe Asachi" Technical University of Iași, Faculty of Chemical Engineering and Environmental Protection, dancasca@tuiasi.ro 
ANCA IRINA GALACTION,
"Grigore T. Popa" University of Medicine and Pharmacy, Iași, Faculty of Medical Bioengineering

pages 39 - 52    Download
Abstract
The algal biomass offers great potential as a sustainable feedstock which can be processed for the third generation bioethanol production, due to its many advantages: rapid growth rate, the ability to accumulate important amounts of carbohydrates, all the materials produced are nontoxic and biodegradable. However, in order to produce high concentrations of ethanol, it is necessary to convert all specific carbohydrate components of microalgae: glucan, sulphated polysaccharides, mannitol, alginate, agar, and carrageenan. This paper describes different types of algae and presents the main steps for the technology employed in the production of third generation bioethanol.
Keywords: bioethanol; continuous fermentation; microalgae; seaweed.

Graphene Obtained by Pyrolytic Decomposition in N2 Atmosphere

CĂTĂLINA NUȚESCU DUDUMAN, "Gheorghe Asachi" Technical University of Iaşi, Department of Materials Science, catalinanutescu@yahoo.com
JOSÉ MARÍA GÓMEZ DE SALAZAR Y CASO DE LOS COBOS,
Complutense University of Madrid, Spain, Department of Materials Science and Metallurgical Engineering
MARÍA ISABEL BARRENA PÉREZ,
Complutense University of Madrid, Spain, Department of Materials Science and Metallurgical Engineering
LAURA GARCIA SANCHEZ,
Complutense University of Madrid, Spain, Department of Materials Science and Metallurgical Engineering
CONSUELO GÓMEZ DE CASTRO,
Complutense University of Madrid, Spain, Department of Materials Science and Metallurgical Engineering

pages 53 - 60    Download
Abstract
Graphene, an allotrope of carbon, is study in the last years because posed interesting chemical, optical and electrical properties. The paper describes the graphene obtaining method by the pyrolytic decomposition. As  raw materials was used epoxy resin. The product of pyrolytic decomposition of the epoxy resin was characterized using several techniques: scanning electron microscopy (SEM), transmission electron microscopy  (TEM),  X-Ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR). Experimental results indicate the nanostructure stacking of multiple layers of graphene; at 500 nm we can observe lamellas of graphene. On the base of the experimental data we can conclude that the pyrolytic decomposition product is graphene.
Keywords: Graphene, Epoxy resin, Pyrolysis, Characterization.

Abstract of PhD Thesis:  
Extraction, Identification and Antioxidant Activity of the Phenolic Secondary Metabolites Isolated from the Leaves, Stems and Fruits of Two Shrubs of the Ericaceae Family

OANA-CRINA BUJOR, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection, oana_crin@yahoo.com

pages 61 - 62    Download

Habilitation Thesis Summary:
Sorption - Separation Method of Chemical Compounds from Aqueous Media

DANIELA ȘUTEU, "Gheorghe Asachi" Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection, dsuteu@ch.tuiasi.ro

pages 63 - 68    Download