悬浮TiO_2-铂电极体系光电催化降解染料

文章采用悬浮TiO2-铂电极体系,以悬浮TiO2作为光催化剂,在两片铂电极间施加一定的电压,研究了染料Procion Red MX-5B在NaCl和Na2SO4电解质溶液中的光电催化降解。光电催化的效率与NaCl溶液的浓度和外加电压密切相关,在0.3mol/L的NaCl溶液中,外加电压8V的条件下,10min内染料的脱色率达到95%,而同时间内光催化脱色率只能达到35%。当外加电压超过5V时,电降解几乎与光电催化具有相同的染料脱色率,然而电降解并不能使染料降解的中间物矿化。光电催化能够在反应的最初一个小时去除溶液中80%的TOC,相同时间内光催化能够去除50%。光电催化与光催化都不能完全矿化所处理的染料,原因在于溶液中生成了非常稳定的降解产物。在Na2SO4溶液中,外加电压只能轻微的提高染料的脱色率,但却不能促进中间产物的分解。

Photoelectrocatalytic Degradation of Procion Red MX-5B in TiO2 suspension-Pt Electrode System

In the present study,photo-electro-catalytic (PEC)degradation of Procion Red MX-5B was investigated in aqueous NaCl and Na2SO4 solutions which were used as electrolytes in the PEC degradation of the dyestuff,Procion Red MX- 5B,and TiO2 particles dispersed into water were chosen as the photo-catalyst combined with two platinum electrodes. It was found that PEC degradation efficiency was dependent on the concentrations of aqueous NaCl solution and the applied potentials. Electro -degradation could be as powerful as PEC degradation upon dye de -colorization when the potential exceeded five volts. However,it could not mineralize the dyestuff degradation intermediates by itself alone. Neither of PEC and photo-catalytic oxidation (PCO)could fully mineralize the treated dyestuff in NaCl solution due to the remains of very stable degradation products existed in the solution. It was also found that the applied potential could barely improve the dye de-colorization and had no contribution to the mineralization of the intermediates in Na2SO4 solution.