Ludmila N. Shiyan

Study of the Mechanism of Interaction of Microwave Plasma Discharge with Solutions of Organic Substances

This paper reports about results describing the mechanism of oxidation-reduction reactions occurring in the microwave plasma interaction with organic compounds solutions. Air and argon were used as the plasma gases in the experiments on disrupture of aqueous liquid organic compounds. Application of inversible redox indicator of methylene blue (MB) showed that disrupture of organic substances in microwave plasma was based on redox reactions. It was found that MB highest efficiency in the solution took place when air plasma-supporting gas was used.

Colloid stability of iron compounds in groundwater of Western Siberia

The paper reports on experimental modeling of the colloid system composition in natural groundwater. Iron hydroxide is found to be the main component of natural colloid systems. It is shown that silicon compounds and dissolved organic substances (DOS) stabilize iron hydroxide (III), forming a stable colloid system, and preclude coagulation. The presented results suggest that CaCl2 and AlCl3 electrolytes affect the coagulation stability of synthesized model colloid solutions.

Influence of the modification process on the properties of AlOOH nanofibers

A procedure of bulk modification of aluminum oxhydroxide AlOOH during synthesis using manganese(II) ion as the modifying agent was studied. The physicochemical properties of the modified AlOOH fiber were examined. It was found that the presence of manganese(II) ions in solution affected the composition of the products of the reaction between aluminum nanopowder and “liquid water.” The phase composition of the reaction products was examined by X-ray diffraction and differential thermal analysis techniques. It was shown that, for solutions with the manganese ion concentration varying from 0.02 × 10−3 to 40 × 10−3 mol l−1, the degree of amorphicity and the proportion of the AlOOH phase tended to increase. A modification mechanism involving the participation of manganese ions in the AlOOH nanofiber growth process was proposed.

Method of removal of colloid iron from groundwater of Western Siberia region by using of carbon dioxide

Water objects of Siberia north contain impurities in water in colloid form. The impurities are stable to physical and chemical influence. Search ways of decreasing of natural colloid solutions stability is topical issue. Destruction of colloid particles makes it possible to produce qualitative potable water. In the present work factors influenced on aggregate stability of colloid solutions are represented. It is shown that a disperse phase of natural colloid systems consists of iron and silicium ions and humic organic substances in the ratio 5.6 mg/L:20 mg/L:2.2 mg/L, respectively. Calculated electrokinetic potential of colloid solutions is in the range from -23 up to -32 mV. Stability of colloid iron is studied at the presence of CaCl2 and AlCl3 electrolits. Coagulation thresholds of CaCl2 and AlCl3 are equal to 1.25 mmol/L and 0.0074 mmol/L, respectively. Furthermore, it is shown pH is also influenced on stability of the colloid system. When pH of solution is 4.5 colloid iron system coagulates. This fact allows developing a method of removal of colloid iron by temporal decreasing of pH by using of carbon dioxide. This method is ecologically safe and allows simplifying technology of water-preparation due to exception of the thin filtration which is used for removal colloid particals. The pH renewal is spontaneous process which is going while carbonization is going. Thermodynamic calculations of reactions describing the destruction mechanism of colloid iron are represented.

Destruction of humic substances by pulsed electrical discharge

Currently, the water recourses in the territory of Tomsk region are groundwater which is limited to the high concentration of iron and manganese ions and organic substances. These impurities present in water in different forms such as soluble salts ant the colloid forms. Therefore, the present work is a part of a continuations researcher of the processes in natural waters containing humic substances at the influence of pulsed electrical discharges in a layer of iron pellets. It is shown that the main stage of water purification process of humic substances during treatment by pulsed electric discharge in the layer of iron granules is a difficult process including several stages such as formation of iron oxyhydroxide colloid particles, sorption and coagulation with humic macromolecules substances, growth of particle dispersed phase and precipitation. The reason for the formation and coagulation of the dispersed phase is a different state of charge of the colloid particles (zeta potentials of (Fe (OH)3) is +8 mV, zeta potentials of (Humic substances) is -70 mV. The most intense permanganate oxidation reduction to the maximum permissible concentration occurs at the processing time equal to 10 seconds. The contact time of active erosion products with sodium humate is established and it equals to 1 hour. The value of permanganate oxidation achieves maximum permissible concentration during this time and iron concentration in solution achieves maximum permissible concentration after filtration.

Using the chemical dosimeter to measure the integral characteristics of the pulsed electron radiation

The paper presents the results on the study of the potassium nitrate dosimeter to estimate the characteristics of the pulsed electron radiation with an electron energy of 500 keV. One of the final products formed after potassium nitrate radiation is nitrite ion, whose radiation-chemical yield is constant and it equals 1.6 ion/100 eV. The measured concentration of nitrite ion with the Griess reagent enables to estimate the absorbed dose in any geometrical point of the irradiated volume. The comparable results of the magnitude of the absorbed dose obtained using a film dose color indicator are presented. The possibility to use an aqueous solution of potassium nitrate as a dosimeter, which is equivalent to the irradiated aqueous mediums, is studied. It is shown that the use of the potassium nitrate as a dosimeter is restricted due to the change in radiation-chemical yield of nitrite ions in solutions of different concentration.

Destruction of organic compounds in gaseous and liquid media in plasma microwave discharge

The paper introduces the results of experimental studies of organic compounds molecular destruction in gaseous and liquid media using a microwave discharge plasma at atmospheric pressurem. Air and argon were used as the plasma gases in the experiments on disrupture of aqueous liquid organic compounds. By applying of inversible redox indicator of methylene blue (MB) it was shown that disrupture of organic substances in microwave plasma had been based on redox reactions. It was found that MB highest efficiency in the solution took place when air plasma-supporting gas had been used. New materials such as hydrogen, acetylene, ethylene, carbon nanostructured material were generated as the result of destruction of natural gas molecules in microwave discharge plasma.

Developing Nanomaterials with Given Properties Based on Aluminum Oxyhydroxide

This paper reports about the method of modified nanomaterials. The aluminum oxyhydroxide was modified by manganese ions (II) during the synthesis. It was shown that modified aluminum oxyhydroxide has new function properties such as catalytic properties. It was shown that the modified aluminum oxyhydroxide with the high concentration of manganese ions (II) could be used in the reaction of the oxidation of methane.

Study of Destruction of Organic Substances in Water Solutions by Pulsed Electrical Discharges in the Iron Granules Layer

The paper reports on the interaction of an electric discharge with solutions of organic substances in the electric reactor with iron loading. A colored water solution of organic substances with well-studied properties such as methylene blue (MB), furatsilin and eosin is used. The chosen organic substances allow to demonstrate the redox reactions, destruction of organic substances and their adsorption. It is found out that the process of direct interaction of organic substances with the discharge is 40%. Efficiency of sorption processes on iron load depends on the properties of the dissolved organic substances and for the MB is 21%, for furatsilin is 42% and for eosin is 63%. Post-effects have been observed after the action of the discharges and have shown activity for 24 hours. The obtained results allow modeling the mechanism of transformation of complex organic compounds e.g. humic substances or oil products.

Removal of Iron Colloid Substances from Aqueous Solutions Using Pulsed Corona Discharge

Pulsed electric discharge has been used for the removal of iron colloid substances from aqueous solutions. The residual concentration of organic substances in aqueous solution depends on the pulse repetition rate. The maximum decrease in organic substances concentration was observed at the pulse repetition rate of 800 pps. Comparison of the results obtained for iron colloid solutions containing humic substances and solutions of humic subtances with no colloids shows that the highest removal efficiency of organic substances was obtained when no iron and silicon ions were present in the solution. The results of our experiments suggest that pulsed electric discharge treatment for the removal of organic substances from natural waters is more efficient at an after-treatment stage, after precipitation of colloid substances.