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Chemical Bulletin of Kazakh National University
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This is an Open Access Journal

Open Access journal
ISSN (Print) 1563-0331 - ISSN (Online) 2312-7554
Published by Al-Farabi Kazakh National University

[1 journal]

Study of the influence of surface-active substances on the initial stage
of copper electrodeposition
- Authors: Amantay Dalbanbay, Aleksandr Nikolayevich Nefedov, Roza Akhmetbekovna Nurmanova, Mikhail Kasymovich Nauryzbayev
  Pages: 12 - 19
  Abstract: In this research, the effect of surface-active substances (CMC and DFP) on the electrolysis of copper by cyclic voltammetry (CVA) and chronoamperometric methods was studied. The working electrode was a glassy carbon electrode. Studies show that in the acid solution of copper sulfate (10-2 M CuSO4 + 0.5 M H2SO4), the three-dimensional electrochemical deposition of copper occurs by the mechanism of instantaneous nucleation. The added surface active substances affect the dischargeionization process, the standard electroreduction potential is shifted to the negative side. The added DFP reduces the cathodic peak current, and the addition of CMC results in its increase. At the deposition potentials corresponding to the regions up to the CVA peak current (here, still, the mixed electrodeposition kinetics), the number of nuclei formed is greater for a pure solution, but at current decay potentials, where the diffusion regime takes place, the nuclei population density (NPD) is higher for solutions with surfactants. The most powerful effect here is caused by the addition of DFP. In the case of mixed additives, the NPD values are close to those of the CMC, obviously indicating the preferential adsorption of CMC, whereas the DFP as complexes with copper ions is closer to the near-electrode region.
  PubDate: 2018-03-14
  DOI: 10.15328/cb890
Development of the technology for obtaining new hydrogel materials based
on acrylic monomers
- Authors: Nazerke Dauletbayevna Nurabay, M. Abutalip, Raikhan Kulymbetovna Rakhmetullayeva, Grigoriy Alekseevich Mun
  Pages: 20 - 29
  Abstract: Smart water-soluble polymers and hydrogels are capable to reversibly react to insignificant changes of the medium properties (pH, temperature, ionic strength, a presence of some substances, illumination, electric field). The reacting of a system is visible to the naked eye (the formation of a new phase in a homogeneous solution, or compression of the hydrogel). The properties of such polymers and hydrogels are considered. For the first time, the stimuli-responsive polymeric hydrogels based on N-isopropylacrylamide (NIPAAM), 2-hydroxyethyl acrylate (HEA) and acrylic acid (AA) have been synthesized by free initiation of radical copolymerization. The purpose of the research is to obtain stimuli-responsive cross-linked terpolymers based on N-isopropylacrylamide, 2-hydroxyethyl acrylate and acrylic acid and study their physicochemical properties. The physicochemical methods such as scanning electron microscopy, differential scanning calorimetry, infrared spectroscopy, gravimetry, cathetometric and thermogravimetric analyses were used in this study. To determine the thermal and pH – sensitivity of the modified copolymer, the effect of temperature on the NIPAAM-НEA-AA nets (in different pH media) was studied. They are characterized by a thermally induced collapse and a dependence on a medium pH. The interaction of copolymers with drugs such as lincomycin and gentamicin was studied for using the new copolymers as a drug carrier. To study the antibacterial properties and the transportation of physiologically active substances of hydrogel, the elimination of specially prepared bacteria by hydrogels with various medicinal ingredients were conducted.
  PubDate: 2018-03-14
  DOI: 10.15328/cb959
Synthesis of molybdenum and tungsten modified composite systems based on
bisorbent from rice husk
- Authors: Duisek Haisagalievich Kamysbaev, Bazarbai Alibayevich Serikbaev, Galina Sergeevna Arbuz
  Pages: 4 - 11
  Abstract: The article presents results of the synthesis of a new composite material modified with polyvalent metals. Rice husk was chosen as a raw material for obtaining a carrier – a bisorbent consisting of carbon and amorphous silicon oxide. The sorption material was obtained from the products of thermal decomposition of rice husks. Further it was modified with ammonium salts of molybdenum and tungsten: (NH4)6Mo7O24·4H2O and (NH4)2O·12WO3·5H2O in Mo/W ratios: 5/5 wt. %, 10/5 wt. % and reducted by heating in a stream of hydrogen. The registration of the voltammetric curves in the medium of 1-methyl-4-piperidone was carried out in various background electrolytes: 0.2 M Li2SO4, pH = 6.36 and 0.1 M KOH, pH = 13, 2,5·10–2 M K2HPO4 + 2,5·10–2 M NaH2PO4, pH = 6.86. Differential voltammetric curves were analyzed. The electrochemical activity of the obtained modified composites in the potential range from -1.2 V to 0.5 V was determinated. The mechanism of the proceeding electrochemical processes on these modified electrode materials has been studied. The possibility of further use of synthesized composite systems based on bisorbents from the rice husk for the electrochemical reduction of 1-methyl-4-piperidone was shown.
  PubDate: 2017-12-27
  DOI: 10.15328/cb977

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