Ag/TiO_2对含酚废水的光电催化降解

Electro-Photocatalytic Degradation of Phenol in Wastewater Using Ag/TiO_2 Photocatalysts

以悬浮态Ag/TiO2为光催化剂,网状Ti为电极,以含酚废水为模型化合物,进行三维立体电极光电催化降解有机污染物研究。结果表明,外加阳极偏压可有效提高Ag/TiO2光催化降解反应速度,Ag的质量分数为1.5%时苯酚光电催化降解率达最大值。外加电压对光催化降解反应速度的影响存在双峰效应,最佳电压值分别为10和20V。在光电催化反应器中加载20V阳极偏压,光电催化氧化苯酚的去除率较光催化氧化提高了35%,大大高于苯酚光催化氧化与电化学氧化去除率的总和。电解质NaCl的加入可大幅度提高Ag/TiO2对苯酚光电催化降解速度,90min苯酚去除率可提高43.9%;导走光生电子、抑制光生电子空穴复合、增加电子向吸附氧分子的传递是Ag/TiO2催化体系表现出较高活性的主要原因。

In the present work, suspended Ag/TiO2 was used as the catalyst, Ti mesh as the electrode, and a evaluated. The results show that the anode potential bias favors the photocatalytic degradation of phenol. The maximum phenol removal efficiency was achieved when TiO2 with 1.5% silver loading was used. Two optimal voltage values for the Ag/TiO2 electro-photocatalysis reaction were 20 and 10V, respectively. Addition of electrolyte NaCl increased the phenol removal efficiency of Ag/TiO2 electro-photocatalysis from 49.7% to 93.6%. Enforced electric field can drive photogenerated electrons away from the photocatalyst surface, and the enhanced photocatalytic activity is mainly caused by the low recombination rate of electrons and holes and the higher rate of electron transfer to adsorbed oxygen.