Studies on photo-electro-chemical catalytic degradation of acid scarlet 3R dye

摘要

A new type of photo-electro-chemical catalytic reactor was designed. Cathode and anode of the new reactor were made of high-purity graphite and titanium dioxide electrode respectively. A saturated calomel electrode (SCE) was used as the reference electrode. Under the condition of ultraviolet radiation and anodic bias-voltage, acid scarlet 3R was degraded by the process of photoelectrocatalysis with titanium dioxide electrode in anodic compartment, while it was degraded by electrogenerated Fenton''s reagent and hydrogen peroxide through reducing dissolved oxygen with graphite electrode in catholyte. The new reactor made the best use of photogenerated holes and photogenerated charge on the anode of the new reactor, which achieved the purpose of degrading acid scarlet 3R in the cathodic and anodic compartments simultaneously, i.e. "two electrodes and double effect". The experimental results showed that, compared with other photoelectrocatalysis reactors ("two electrodes and single effect" reactor), the new reactor has obviously enhanced the degradation of acid scarlet 3R dye. With the concentration of the dye being 30 mg • L~(-1) in water, under the operating conditions that when the inert supporting electrolyte concentration was 0.02 mol · L~(-1) sodium sulfate, initial solution pH = 3, and cathodic potential -E_c = 0.66 V, the highest decolorizing efficiency of 92% was accomplished in cathodic compartment, and that of 60% in anodic compartment.