9 research outputs found
Discrimination Issues in the Process of Personnel Selection
The paper discusses the concept of employment discrimination and its types, depending on the causes. The analysis of problems of social (gender and age) and psychological (racial and religious affiliation, disability) discrimination is given. The consequences of discrimination from the perspective of the employee and the employer are considered. The unfavorable situation in Russia in terms of high levels of discrimination is shown. The main objective trend, which will lead inevitably to the reduction of discrimination in the labor market, is revealed
Adsorption of tartrazine from an aqueous solution by octadecyltrimethylammonium bromide-modified bentonite: Kinetics and isotherm modeling
Chemical and electrochemical study of the inhibition of calcium carbonate precipitation using citric acid and sodium citrate
<p>This work investigated the inhibitive effect of citric acid (CA), sodium citrate (SC), and their mixture (CA–SC) on the CaCO<sub>3</sub> scale. The study was carried out using chronoamperometry, impedancemetry, and fast-controlled precipitation methods. The electrochemical study showed that CA provides a slight inhibition of CaCO<sub>3</sub> deposit at a concentration of 70 ppm on stainless steel surface. The use of SC alone inhibits very little the formation of scale. The use of the mixture (50% of CA and 50% of SC) with small concentration led to significant inhibition of the CaCO<sub>3</sub> formation. The deposits formed were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). The XRD showed that the intensity of the preferential orientation (1 0 4) corresponding to crystallographic plans of calcite decreases and the SEM demonstrated a decrease in calcite crystal size from 10 to about 2 μm.</p
Electrochemistry of Nanocrystalline La0.5Sr0.5MnO3 Perovskite for the Oxygen Reduction Reaction in Alkaline Medium
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Adsorption studies of an azo dye using polyaniline coated calcined layered double hydroxides
International audienceIn this study, novel composite polyaniline/calcined layered double hydroxides was synthesized through the chemical method using the ammonium persulfate as an oxidant and investigated for its behavior in selective and high adsorption of tartrazine dye from an aqueous solution in a batch system. Scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer–Emmett–Teller method and thermogravimetric analysis were carried out. The effects of solution pH, initial concentration and contact time were investigated. The adsorption processes show that the max-imum adsorption capacity of tartrazine was 487.8 mg/g, obtained for the MgAlC-PANI composite and well fitted to Langmuir isotherm model. The adsorption processes followed the pseudo-second-order kinetics model with a very high correlation coefficient of 0.998 < R2 < 1. The regeneration studies revealed that the tartrazine loaded MgAlC-PANI could be reused for four consecutive cycles
Influential factors on oxygen reduction at La1-xCaxCoO3 electrodes in alkaline electrolyte
Calcium alginate-organobentonite-activated carbon composite beads as a highly effective adsorbent for bisphenol A and 2,4,5-trichlorophenol: kinetics and equilibrium studies
International audienceToday toxic phenolic compounds are a major source of pollution and are mainly the result of various industrial wastes such as plastics, polymers, insecticides, etc. In this context, the originality of our study is a first as we used a new composite material assembled by mixing activated carbon (AC), organo activated bentonite (OAB), and alginate (A). The prepared adsorbent materials were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and point of zero charge (pH(PZC)). The influence of various factors such as contact time, pH, adsorbate concentration, and temperature on the adsorption of bisphenol A (BPA) and 2,4,5-trichlorophenol (TCP) has been investigated. The equilibrium data were fitted well by Freundlich isothermal model and the maximum adsorptions of BPA and TCP onto alginate/organo activated bentonite/activated carbon beads (A-OAB-AC), were 368.2 and 385.1 mg.g(-1), respectively. The adsorption of BPA and TCP was observed to follow pseudo-second order mechanism as well as the thermodynamic parameters confirm also endothermic spontaneous and physiosorption processes. In addition, the resulting adsorbent reusability was demonstrated by at least six cycles, indicating that the A-OAB-AC can be used as a promising adsorbent for removal of toxic pollutants from aqueous solutions