Comparison of the Characteristics of DC Discharges with a Liquid Anode and a Liquid Cathode over Aqueous Solutions of Zi
- PDF / 987,653 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 16 Downloads / 180 Views
MA DIAGNOSTICS
Comparison of the Characteristics of DC Discharges with a Liquid Anode and a Liquid Cathode over Aqueous Solutions of Zinc Nitrate D. A. Shutova,*, A. I. Artyukhova, A. N. Ivanova, and V. V. Rybkina,** a Ivanovo
State University of Chemistry and Technology, Ivanovo, 153000 Russia *e-mail: [email protected] **e-mail: [email protected]
Received March 5, 2019; revised April 29, 2019; accepted May 23, 2019
Abstract—Results of systematic measurements of the electric and energy characteristics of a dc gas-discharge plasma in contact with a liquid are presented. The discharge was excited in atmospheric-pressure air over aqueous solutions of Zn(NO3)2. The experiments were carried out with two types of discharge: with a liquid anode and a liquid cathode. An H-shaped plasma–solution cell was used, whose branches were separated by a membrane to exclude the effect of possible chemical and/or electrochemical processes at the electrode immersed in the solution in one part of the cell on the characteristics of the metal–plasma–solution system in the other part of the cell. The discharge current was varied from 20 to 80 mA, and the zinc nitrate concentration in the solution was varied from 5 to 100 mmol/L. The current–voltage characteristic of the discharge, the electric field strength, and the near-electrode potential drops were measured. Using the geometrical characteristics of the discharge, the current densities are calculated in both the positive column and the region of the contact between the discharge and the solution. From results of spectral measurements, the vibrational temperatures of vibrationally excited nitrogen molecules in the N2(C3Πu) state and the temperature of the neutral plasma component are determined. The reduced electric field is calculated in the entire ranges of zinc nitrate concentrations and discharge currents under study. The results obtained for discharges with a liquid cathode and a liquid anode are compared. The results of this work can be used to simulate gas-discharge plasmas over aqueous solutions, in particular, to calculate the densities and fluxes of active particles from the plasma to the solution. DOI: 10.1134/S1063780X19100052
1. INTRODUCTION The area of application of plasma–solution systems, i.e., systems in which gas-discharge plasma is in contact with the liquid phase, has expanded significantly in recent years [1]. Without going into a detailed enumeration of specific applied problems solved with the help of the effect of plasma on solutions, it is worth highlighting two main directions. The first one is the use of plasma as a tool for the chemical activation of aqueous solutions [2], which can initiate various kinds of redox reactions in the solution, such as the decomposition of organic compounds, reduction of metals, and synthesis of inorganic compounds. The second one is the use of plasma as a tool causing nonequilibrium transfer of the solution components to the discharge zone with their subsequent excitation, which makes it possible to use plasma–solution systems,
Data Loading...
