二氧化钛纳米管阵列光电催化同时降解苯酚和Cr(VI)

Simultaneous Removal of Phenol and Cr(VI) by TiO_2 Nanotube Array Photoelectrocatalysis

采用电化学阳极氧化法在纯钛箔基底上制备了TiO2纳米管阵列,并运用X射线衍射、扫描电镜和电化学工作站对其进行了表征.结果表明,所制样品是锐钛矿相,管径约为100nm,管长约为2μm,在0.5V偏压下光电流最大.以苯酚和Cr(VI)混合溶液为目标污染物,考察了TiO2纳米管阵列光电催化同时去除苯酚和Cr(VI)的反应性能,探讨了催化方式、溶液pH和污染物初始浓度对其催化性能的影响.结果表明,采用光电催化方式,苯酚和Cr(VI)的去除率分别达86.7%和96.9%,而光催化方式下则分别仅为48.2%和65.2%.酸性条件下有利于TiO2纳米管阵列光电催化同时去除苯酚和Cr(VI),且在pH=2时,效果最佳.Cr(VI)苯酚共存体系中,Cr(VI)及苯酚的去除率均较单一组分体系的高;Cr(VI)的还原与苯酚的氧化之间产生了协同效应,共同促进了苯酚与Cr(VI)的去除.

TiO2 nanotube arrays were prepared by electrochemical anodization on pure Ti surfaces.The products were characterized by X-ray diffraction,scanning electron microscopy and electrochemical workstation.The results showed that the prepared sample was anatase with a diameter of about 100 nm and a tube length of about 2μm.The maximum photocurrent could be achieved when the bias potential of 0.5 V was applied on the TiO2 nanotube array electrode.The photoelectrocatalytic properties of the TiO2 nanotube array electrode were evaluated by the simultaneous removal of phenol and Cr（VI）.The effects of catalytic processes,pH values,and various initial concentrations of Cr（VI） and phenol on the removal efficiency of phenol and Cr（VI） were investigated.The results indicated that in the photoelectrocatalytic mode,phenol and Cr（VI） removal ratios were 86.7% and 96.9%,respectively,while in the photocatalytic mode they were 48.2% and 65.2%,respectively.The removal efficiency by photoelectrocatalysis was higher than that by photocatalysis.The acidic solutions were favorable for the photoelectrocatalytic simultaneous removal of Cr （VI） and phenol,and the optimum pH was 2.In the phenol-Cr（VI） co-existed system,phenol and Cr（VI） were more efficiently eliminated than in the single phenol or Cr（VI） system.The reduction of Cr（VI） and the oxidation of phenol produced a synergistic effect,which promoted the simultaneous removal of Cr（VI） and phenol.