2019, Issue 65(69), Fasc. 3 (September)

Contents

pages 1- 8    Download

Electrochemical behavior of TiMoxNby alloys in simulated biological fluid

MARIA MAGDALENA PRICOPI, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection
ROMEO CHELARIU, "Gheorghe Asachi" Technical University of Iași, Romania,
GABRIELA ANTOANETA APOSTOLESCU, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection
NICOLAE APOSTOLESCU, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection
DANIEL SUTIMAN, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection, sutiman@ch.tuiasi.ro

pages 9 - 15    Download
Abstract
The present study explores the electrochemical behavior of Ti-Mo-Nb alloys with: open-circuit potential, potential-dynamic polarization and electrochemical impedance spectroscopy in SBF solution. The paper presents a deep analysis of the processes that take place on the surface of the alloy/electrolyte interface on the electrochemical behavior of the samples under investigation. The measurements were performed in simulated biological fluid (SBF) for one hour of immersion. The EIS results showed that TiMoNb alloys exhibit passivity for open circuit potential.
Keywords: Ti-Mo-Nb alloys; corrosion resistance; SBF solution; biomaterial application.

Photocatalytic degradation of cationic tri-arylmethane dye - Methyl Violet 10B on ZnS catalysts under UV irradiation

NICOLAE APOSTOLESCU, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection
IULIAN MOROȘANU, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection
CORINA CERNĂTESCU, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection
CLAUDIA COBZARU, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection
RAMONA-ELENA TĂTARU-FĂRMUȘ, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection
MIHAELA AURELIA VIZITIU, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection
GABRIELA ANTOANETA APOSTOLESCU, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection, ganto@ch.tuiasi.ro

pages 17 - 25    Download
Abstract
The presence of tri-arylmethane dyes in waste water is an issue of major concern due to the toxic potential to the environment. The conversion of these pollutants into mineral products with minimal energy is a major goal of the world scientific community. In this study, we investigate the photocatalytic degradation under UV light of Methyl Violet 10B, a complex dye with antibacterial, anthelmintic and antifungal effects, used in local administration or in the textile industry. The reaction conditions (irradiation time, radiation nature and catalyst loading) were evaluated in order to obtain an optimum time to discolouration, the results suggesting that the used ZnS can be successfully used to degrade the Methyl Violet 10B dye.
Keywords: Methyl Violet 10B; photocatalysis; ZnS catalysts; UV light; wastewater.

Simple methods for quantitative determination of sulphate ions from aqueous media with industrial applications

LARISA ANECHIŢEI, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection
TATIANA COJOCARU, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection
IOANA-GIORGIANA MUNTEANU, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection
LAURA BULGARIU, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection, lbulg@ch.tuiasi.ro

pages 27 - 37    Download
Abstract
In this study, two simple methods (conductometric titration and turbidimetric method) have been used for the quantitative determination of sulphate ions from aqueous media. Both methods are based on the reaction between sulphate ions and BaCl2, when a white precipitate (BaSO4) is obtained. The main advantage of this reaction is that the formation of the BaSO4 precipitate occurs almost under any experimental conditions. Therefore, the two methods were comparatively examined to establish their applicability limits in the quantitative determination of sulphate ions. Thus, several important analytical parameters, such as usable concentration range, detection limit, precision, selectivity, etc., were evaluated based on the experimental results, in each case. The results included in this study show that these two methods complement each other, and allow the determination of sulphate ions from a wide range of industrial samples.
Keywords: Sulphate determination; conductometric titration; turbidimetric method; aqueous solution; industrial applications.

Natural and artificial dehydratation of apples and bananas. Comparative studies

CLAUDIA COBZARU, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection
ANA OLTEANU, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection
ADRIANA MARINOIU, National Research and Development Institute for Cryogenics and Isotopic Technologies - ICSI Râmnicu Vâlcea, Romania
CORINA CERNĂTESCU, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection, ccernatescu@yahoo.com

pages 39 - 49    Download
Abstract
In this study, the natural and artificial dehydration of apples and bananas was performed. The products were dehydrated naturally, at room temperature, and artificially in the oven, radiator and microwave. The resulting dehydrated products were analysed for the vitamin C and carbohydrates content, total acidity and dry substance (in this case sugar content). Experimental results showed that after dehydration, all products still contain small amounts of vitamin C, and the sugar values for dried apple samples are higher than for dry bananas. Furthermore, for all dehydrated products, the total acidity is low and the pH is high, making dried products, compared to fresh ones, more tolerable for consumers with digestive problems, as detailed below.
Keywords: natural dehydration; artificial dehydration; apples; bananas.

Experimental equipments used in the study of carbon dioxide absorption (II)

RAMONA-ELENA TĂTARU-FĂRMUȘ, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection, rtataru@ch.tuiasi.ro
RAMONA-ELENA MOLDOVANU, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection
MARIA HARJA, "Gheorghe Asachi" Technical University of Iași, Romania, "Cristofor Simionescu" Faculty of Chemical Engineering and Environmental Protection

pages 51 - 58    Download
Abstract
Carbon dioxide is a component of industrial gaseous fluxes and is frequently removed to improve gas quality or to prevent catalyst poisoning. It is obvious that CO2 emissions play a primary role in global warming. There are several ways to remove CO2 - absorption, adsorption, cryogenic separation, permeation through membranes and chemical conversion. The industrial plant for absorption consists of the absorption unit, the regeneration unit and auxiliary equipment. Over time, the absorption process investigations were carried out using innovative equipment, which would improve the performance of this process.
Keywords: absorption; carbon dioxide; experimental devices; solvents.