硫掺杂二氧化钛的光催化活性及其对微囊藻毒素的降解

Photocatalytic Activity of Sulfur Doped TiO2 and Degradation of Microcystin-LR

为了更方便高效和绿色环保处理水中的微囊藻毒素（MC-LR）,采用溶胶-凝胶法制备了硫（S）掺杂的二氧化钛（TiO2）纳米光催化剂粉体（S-TiO2）,利用X射线光电子能谱（XPS）、X射线衍射（XRD）以及紫外可见光的反射光谱,分析测定了催化剂的结构特征,并以浓度为0.1μg/mL的MC-LR的光降解效果考察了其光催化活性,研究其光降解条件。结果表明,本实验制备的催化剂为锐钛矿结构,S以S＋6的形式进入TiO2晶格。催化剂的最优制作工艺为：掺杂量（[S]/[Ti]）0.25,500℃下煅烧3h,且制备的S-TiO2具有较好的稳定性和回收性,重复利用5次,降解率仅下降3.98%;最优MC-LR可见光降解工艺为：光强3 000lx,催化剂投加量0.1g/L,反应时间16h。在此催化剂制备条件以及可见光降解反应条件下,MC-LR的降解率为100%,残留量低于WHO规定的藻毒素含量限值。

In order to remove microcystin（MC-LR）more easily,efficiently and eco-friendly,the sol-gel method was used to synthesize a sulfur doped TiO_2 photocatalyst（S-TiO_2）.The catalyst was characterized using UV-VIS diffuse reflectance spectroscopy（DRS）,X-ray diffraction（XRD）and X-ray photoelectron spectroscopy（XPS）.Photocatalytic degradation of the cyanotoxin microcystin-LR（MC-LR,0.1μg/mL）under visible was investigated to identify optimal conditions for S-TiO_2 synthesis and for MC-LR degradation.Results show that the TiO_2 crystal phase is anatase and the sulfur is fully oxidized,S（VI）.The optimal conditions for S-TiO_2 synthesis is a mole ratio（S∶Ti）of 0.25 and calcining the product at 500℃ for 3 h.The S-TiO_2 photocatalyst was stable and the degradation rate decreased only 3.98%after five cycles of recovery and reuse.At a catalyst dose of 0.1 g/L and a reaction time of 16 hat 3000 lux,the MC-LR（0.1μg/mL）was completely removed（100% degraded）and the treated water complied with algal toxin limits set by the WHO and China,which is proved to be the most effective MC-LR degradation craft.