Studies On Photo-electro-chemical Catalytic Decolorizing Degradation Of Dye Wastewater

A new type of photo-electro-chemical catalytic reactor was designed. Cathode and anode were made of high-purity graphite and titanium dioxide electrode respectively. A saturated calomel electrode (SCE) was used as reference electrode. A ultraviolet mercury lamp was used as lamp-house. Dye wastewater was photo-electro-chemical degraded in the reactor. The influence of some factors was studied, including cathodic potential, initial solution pH value and ferrous concentration. Under the condition of UV irradiation and electricity, dye wastewater was photo-electro-chemical degraded not only with titanium dioxide electrode in anodic compartment, but also in cathodic compartment. It's the first time that degrade dye wastewater in the cathodic and anodic compartments simultaneously, i.e. "two electrodes and double effect". Compared with simple photoelectrocatalysis, the new type of reactor enhanced the degradation of dye wastewater obviously.In the reactor, the applied anodic bias prohibit "charge-hole" combination in titanium dioxide anode, and the electro-Fenton's reagent is the key to degrade organic compound of catholyte in which hydrogen peroxide generated through an electrochemical reduction process of dissolved oxygen. The experimental results showed that on the best operating conditions that the inert supporting electrolyte concentration was 0.02mol·L-1, ferrous concentration was 0.036mmol·L-1, initial solution pH = 3, and cathodic potential -Ec = 0.66V, the highest decolorizing efficiency of 97.7% was obtained in cathodic compartment, and 87.5% in anodic compartment when the concentration of acid scarlet 3R dye was 30mg·L-1 Compared with other reactors, i.e. "two electrodes and single effect", the new type of reactor enhanced the degradation efficiency of dye wastewater 110% about.The further studies showed that the reactor can effectively degrade other kinds of dye wastewater including reactive brilliant red, methyl orange, direct fast black, fuchsin basic and industrial wastewater. The experimental results showed that the new type ofreactor has widely applicability on decolorizing and degrading dissoluble and intractable dyeing wastewater.