Assessing the Chemical Activity of Plasma Radiation

The chemical activity of products formed under the action of spark discharge plasma radiation in aqueous solutions was investigated. The red-ox reactions with the test substances were used to determine of chemical effect of plasma radiation. Aqueous solutions of Mohr's salt and potassium permanganate were used as test substances. Two cases of irradiation were studied: directly on the test substance solution (case 1) and on water, after which the treated water was mixed with the test substance (case 2). The yield of oxidizing equivalents formed in the sample during treatment was determined for the both cases by oxidation of ferrous ions Fe2+  Fe3+ in the Mohr's salt solution. The yield of reducing equivalents was determined by reduction of manganese Mn7+  Mn2+ in solution of potassium permanganate. Three processing modes were used. Mode 1, the direction from the discharge area to the surface of treated liquid has been opened. Mode 2, the direction from the discharge area to the surface of treated liquid was blocked by an opaque plate. Mode 3, the discharge cavity was completely closed by a 2.3 mm thick quartz glass. For comparison, the yield of oxidizing and reducing equivalents under the action of mercury lamp radiation ( = 253.7 nm) was measured. For the complete yield of reductants and oxidizing agents, the yield of suitable reactions was taken on the 4th day after treatment. It was shown that the main mechanism of the reaction under plasma radiation is indirect action.