Problems of Chemistry and Chemical Technology

Solvent Delignification of Kenaf and Sugar Sorghumstems

The chemical composition of stalks of kenaf and sugar sorghum was studied. Established that the kenaf and sugar sorghumstalks contain more cellulose, pentosans, minerals and less lignin than wood. The influence of main technological parameters on the quality indexes of organosolvent pulp obtained from kenaf and sugar sorghum stems was investigated. The possibility of bleaching organosolvent pulp obtained from stems of kenaf using hydrogen peroxide without chlorinecompounds to 80 % whiteness was experimentally proved.

The Determination of Stability of Platinum Catalyst of Selective Reduction of Nitrogen Oxides

In the article we present research results of the activity change by platinum catalyst of selective catalytic reduction (SCR) NOx from the operating time. We propose the method of determining the stability of the catalyst relying on the correlation between the size of crystallite and activity of catalysts. We demonstrate the results of deactivation velocity of different catalysts with respect to time. Based on data of fluorescence analysis and electron microscopy analysis, we demonstrate physico-chemical characteristics of the novel catalyst and samples with various operating time.

Multistage Galvanostatic Method of Electrowinning Copper from Sulphate Solution of Copper Ore Leaching

This paper investigates the process of copper electrowinning from carbonate ore. Copper was leached by sulfuric acid solution. The obtained electrolyte was used for copper electrowinning. We show that step current lowering was the best method to obtain massive cathode deposit or copper foil with 100 % of current efficiency. We make theoretical calculations of the electrolysis process.

Physical Models of Ultrasonic Influence in Liquid Compositions of Epoxy Polymers. Part 1. Physical Model of the Process of Low Frequency Ultrasonic Cavitation

In this paper, we analyze the origin and development of the process of low frequency ultrasonic cavitation in the liquid epoxy oligomer of ЕD-20 brand depending on time of its insonation. We provide the rationale for the physical model of low frequency ultrasonic cavitation in liquid compositions of epoxy polymers. Specifically, it allows choosing effective parameters of this process (frequency, amplitude, intensity) and at the same time ensuring structural integrity of sonicated epoxy compositions.

Synthesis and Characterization of Nanodispersed Powders of Tin Oxide (IV) from Tin Oxalate (II)

We synthesize powders of tin oxide (IV) from tin (II) oxalate by thermal method with and without chemical pretreatment. The microstructures of samples are investigated by XR-diffraction and microscopic methods of analysis. We establish that the powders obtained by both methods have a tetragonal structure of rutile. It was determined that the sample obtained by chemical method followed by heat treatment, has a more porous structure than the sample obtained by thermal method. The lattice parameters and size of crystallite of the samples are calculated.

Rationale Method of Holocellulose Contents Determination in Non-Wood Plant Materials

Method of determination of holocellulose contents in non-wood plant raw materials with taking into account the peculiarities of their anatomical structure and chemical composition was proposed. It was shown that the sustainable level of concentration peracetic acid and hydrogen peroxide determined after seven days of saturation of the solution. The dependences of the holocellulose contents on the duration of treatment different representatives of annual plants were established.

Intensification Effect of Gas Bubbling in the Processes of Ultrasonic Water Disinfection

The paper investigates the influence of various gases on the microorganisms destruction under the ultrasonic water treatment. Under simultaneous action of gas and ultrasound the effective destruction of Bacillus bacteria was achieved for the less process duration as compared with using each agent separately. Water disinfection efficiency at the gas bubbling effect in ultrasound field is about 1,0–1,6 % higher than ultrasound action alone and above 50 % higher than gases effect alone, depending on the gas bubbling nature.

Electrochemical Gas Sensor for Determining Hydrogen Sulfide in Air and Technological Environments

In this paper, we determine the range of potentials, which shows electrochemical stability and corrosion resistance of titanium and catalytically active electrodes based on it in 5 m of HClO4 solution. We reveal that the current-free potentials of these electrodes comply with compromise potentials conjugate reduction reaction of adsorbed oxygen and oxidation of hydrogen sulfide in the presence of hydrogen sulfide. Based on studies of properties of the semiconductor oxide electrocatalysts of transition metals, gas diffusion electrodes are developed.

Biofunctionalization of Nanocomposites Ba¬sed on Magnetite Modified with Mezo-2,3-Dymer-captosuccin Acid

In this paper, we synthesize magnetite-based nanocomposites modified by meso-2,3-dymercaptosuccin acid with biologically active immobilized components (normal human immunoglobulin (Ig) and 2 mercaptonycotin acid (2-MNC). Also, we investigate physical-and chemical properties of magnetic suspensions based on them. We develop the method of chemical surface modification of single-domain magnetite with thiol groups. The obtained nanocomposite is biofunctionalized by normal human immoglobulin by using sulfo-SMCC heterofunctionalized reagent.

Turbidimetry Method of Evaluating the Nanoparticles Sizes in “White Zoles” ZrO2

We determine the possibility of employing turbidimetric method for the express evaluation of particles sizes in “white sols” of zirconium oxide (IV) synthesized by hydrothermal method. We define the phase content in zirconium oxide (IV) synthesized by this method, which mainly comprises the tetragonal modification. We find the particles sizes of zirconium oxide (IV) obtained employing the turbidimetric method, as well as by using the ZetaSizer device. Hence the particles sizes are 62 and 65 nm.