Effect of Different Electrode Structures on Degradation of Methylene Blue Wastewater by DBD Plasma

Abstract

In this paper，the dielectric barrier discharge（DBD）plasma technology is used with 20，80，150，200 meshes copper mesh and copper sheet as electrodes to study the effect of different electrode structure on degradation of methylene blue dye waste water by DBD plasma through investigating the degradation rate of methylene blue，the first-order kinetic constant k，pH value，conductivity as well as COD value. Based on the gas discharge theory，the plasma formation mechanism of dielectric barrier discharge with different electrode structures is analyzed. It is found by the study result that the change of electrode structure will affect the degradation effect of methylene blue dye wastewater. With the increase of mesh number and copper line density of copper mesh，the plasma discharge is transited from discrete type to quasi-discrete type. The uniformity of plasma is increased and the degradation rate of methylene blue is also increased. The first-order kinetic constant k is increased，the degradation rate of methylene blue is also increased in unit time. The pH value of the solution is lower，the conductivity is higher，and the COD value of the solution is lower，and the degradation effect of methylene blue is better. Under the same conditions，the degradation of methylene blue by copper sheet electrode is superior to that by copper mesh electrode.