Effect of spark electric discharge between solid electrodes in water

Generators of spark discharge in air have been developed, where the active factors affecting the object are plasma radiation and the active species formed in the discharge that diffuse to the surface of the object. The first effects observed in the water sample immediately after treatment are a decrease in pH and the formation of nitrous acid. In the experiments, two types of generators are used, which, in the water after treatment, yield a minimum pH value and a maximum concentration of nitrous acid. Processing was carried out in two modes. The first mode is with a discharge cavity completely opened in the direction of the sample (with light). The second mode is with a direction on the sample overlapping with an opaque insert (without light), but with the ability to freely diffuse gaseous products to the surface of the sample. Water samples are observed for 14 days after treatment. The products formed under the action of a low pressure mercury lamp (λ = 253.7 nm) and plasma radiation are compared. The mechanism of generation of the active species in the discharge itself, which can diffuse to the sample surface and be absorbed by water, and species formed directly in water under the action of plasma radiation are considered. The role of plasma radiation in the formation of active species in water is analysed. (paper)