Degradation of indigo carmine using bipolar pulsed dielectric barrier discharge (DBD) in the water-air mixture

Oxidative decolonization of indigo carmine by bipolar pulsed DBD in the water-air mixture was studied using the dynamic UV-Vis spectrum of the solution. Effects of various parameters such as gas flow rate, solution conductivity, pulse repetitive rate and etc., on color removal efficiency of dying wastewater were investigated. Concentrations of gas phase O₃ and aqueous phase H₂O₂ under various conditions were measured. Experimental results show that air bubbling facilitates the breakdown of water and promotes generation of chemically active species. Color removal efficiency of IC solution can be greatly improved by the air aeration under various solution conductivities. Decolonization efficiency increases with the increase of the gas flow rate, and decreases with the increase of the initial solution conductivity. A higher pulse repetitive rate and a larger pulse capacitor Cp are favorable for the decolonization process. Ozone and hydrogen peroxide formed decreases with the increase of initial solution conductivity. In addition, preliminary analysis of the decolonization mechanisms is given.