Catalytic/inhibitory effect of the joint presence of two dyes on its destruction by underwater plasma processes: a tool for optimization parameters of treatment

The underwater plasma was used for the destruction of two-dye mixture. The Direct Blue azo dye and xanthene dye of Rhodamine 6G used as the model pollutants. The concentration of one of them is varied for modeling the processes in which one of the classes of the dye exceeded other dyes. The catalytic/inhibitory effect of the joint presence of two dyes is studied. The effect of initial temperature and the role of H2O2 in the mechanism of destruction were also investigated. It was established that the processes of decay of organic dyes proceed through the stages of the formation of intermediate products, which are catalysts or inhibitors of further degradation processes. An increase in the temperature of the solution has almost no effect on the degree of decolorization of the solution of the dye mixture. It is established that the destruction of Direct Blue 1 occurs under the action of hydrogen peroxide or HO2 radicals, while Rhodamine 6G is destroyed by interaction with hydroxide radicals. The comparison of energy yield values with published data showed that underwater plasma is an effective method for removing the organic dyes from wastewater.