A. I. Maksimov

Physical chemistry of plasma-solution systems

The basic physical, physicochemical, and chemical processes occurring in the plasma-solution systems are considered. Data on correlation between the emission intensity of electrolyte-cathode glow discharge and the rate of nonequilibrium discharge-induced vaporization of the solution are presented. A mechanism for the appearance of the atomic emission threshold of metal atoms in the plasma zone is proposed. The role of chemically active species generated by ion bombardment in chemical processes occurring in solutions is shown.

Physicochemical and Engineering Problems in Studies on Plasma–Solution Systems

The example of an atmospheric-pressure glow discharge with an electrolytic cathode was used to show a significant role of the processes of transfer of solution components to the plasma zone, which were induced by ion bombardment of the surface of the solution. These processes not only determine the chemical composition of the plasma zone but also initiate redox reactions in the gas phase. In turn, the gas discharge alters the properties of the solution, in particular, its acidity, interfering with liquid-phase chemical reactions.

Transfer coefficients of cations and anions upon glow discharge-induced nonequilibrium vaporization of solutions of alkaline earth metal salts

Firing of atmospheric-pressure, electrolytic-cathode glow discharge leads to an effect that is similar to well-known cathode sputtering. This process can be called nonequilibrium vaporization of the solution. Unlike quasi-equilibrium vaporization, the nonequilibrium process entails the transfer of nonvolatile components of the solution to the gas phase. Previously, studying glow discharge with calcium and barium chloride solutions as the cathode, we have shown that the transfer of cations and anions via the nonequilibrium vaporization of the nonvolatile solutes is not necessarily stoichiometric [1].

Comparison of plasma and plasma-solution modifications of polymer materials in the liquid phase

The capabilities of atmospheric-pressure gas-discharge plasma and plasma-solution systems as applied to enhancement of industrial processes in solutions, such as flax bleaching and wood delignification, were analyzed. It was shown that the set of active species generated in the plasma systems corresponds to that required for the processes in question. According to estimates, the efficiency of plasma-solution systems is higher than that of cold atmospheric-pressure plasma. A kinetic scheme for the bleaching processes activated in the plasma-solution systems is discussed.

Sterilization of solutions by underwater electric discharges

A possibility of using low-voltage underwater pinhole discharge for sterilization of aqueous solutions has been considered. It was experimentally established that the time of complete sterilization of a solution is determined by the type of bacterial culture and the number of diaphragms. The posteffect phenomenon has been revealed. The sterilizing property of the solution persists for a long time. An analysis of the results has allowed for identification of the main sterilizing factors, which include chemically active species, discharge-induced shock and sound waves, and UV radiation.

Numerical simulation of the gas phase composition in a glow discharge with an electrolyte cathode

The results of the numerical analysis of the gas phase composition in a system of a glow discharge with an electrolyte cathode are presented. The transfer of the dissolved substance from the solution into the gas phase has been taken into account. The obtained results show that H2O+ is the main positive ion and the concentration of the excited Na atoms in the plasma zone is sufficient for the resonance spectral line of the metal atom to appear.

The nonequilibrium mass transfer of nonvolatile solution components under the action of a glow discharge

The results of the nonequilibrium mass transfer of nonvolatile solution components under the action of a glow discharge using the example of aqueous solutions of salts of alkali earth metals are presented. It has been found that the transfer occurs with the violation of the stoichiometry. The threshold character of the transfer process is confirmed. It is suggested that there exist three modes of transfer.

Yields of hydroxyl radicals and hydrogen peroxide in a glow discharge system with a liquid cathode

A model of the hydroxyl radical yield estimation in a glow discharge-water system is presented. The hydroxyl radical yield has been found. The initial yield of hydrogen peroxide and its effective lifetime have been calculated. The yield of hydroxyl radicals obtained by the suggested model is shown to be in good agreement with the experimental data of other investigators.

Influence of the composition of electrolyte on the kinetics of its nonequilibrium evaporation at the initial steps

Data on the influence of the solute nature and the acidity of solution on the solvent transfer rate are presented. Approximation of different portions of mass transfer curves made it possible to calculate the rate of nonequilibrium evaporation with allowance for the contribution of natural vaporization. It was found that rate of evaporation in acidic solutions of salts is substantially higher than that in neutral solutions. Other conditions being equal, the composition of the solution has a substantial effect on the rate of nonequilibrium mass transfer.

Plasma-assisted oxidative degradation of organic dyes in solution by the joint action of underwater discharge and ozone

Data on the degradation kinetics of two organic dyes in a mixture by the action of electrical underwater discharges and ozone are presented. It has been found that the rate of degradation by the to combined treatment of the both dyes with face discharge and ozone is five times the sum of degradation rates expected on the assumption of the additive effect of each of these factors.