锐钛矿型TiO2光催化降解异噻唑啉酮废水研究

本文制备了自然光照条件下能有效降解异噻唑啉酮模拟废水(主要成分MI和CMI)的锐钛矿型TiO2光催化剂,并通过电镜分析(TEM、HRTEM)和XRD手段对其进行表征,优化了光催化处理异噻唑啉酮模拟废水的反应条件,并分析了异噻唑啉酮的降解产物情况和自然光照条件下羟基自由基的产生情况.结果表明,合成的锐钛矿型TiO2主要暴露面为{101}面,具有较好的异噻唑啉酮去除效果.在500 W氙灯照射下,12~53 mg·L-1异噻唑啉酮模拟废水在催化剂投加量为677 mg·L-1的条件下反应4 h,异噻唑啉酮去除率可以达到97%~100%;当异噻唑啉酮模拟废水浓度升高为141 mg·L-1时,其去除率为77%~80%,最佳反应时间4 h.对异噻唑啉酮降解产物的分析显示,在光催化反应结束时,MI为主要的残留物质,CMI脱氯转化为氯离子和MI,并发现未知有机产物.

Anatase-TiO2 photocatalyst for isothiazolone wastewater treatment

In this paper, anatase-TiO₂ photocatalyst was synthesized to remove isothiazolone from wastewater effectively under natural light irradiation and its properties were analyzed by transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and XRD. The optimal photocatalytic conditions for treating simulated isothiazolone wastewater were studied and the degradation metabolites of isothiazolone and the production of·OH radicals in the solution by anatase TiO₂ under natural light irradiation were evaluated. Results show that the synthesized anatase-TiO₂, which possessed {101} facet as the major exposed plane, exhibited high isothiazolone removal efficiency. When isothiazolone concentration was at 12~53 mg·L^-1, 97%~100% of isothiazolone could be removed from wastewater after photoreaction with 677 mg·L^-1 of anatase-TiO₂ for 4 hours (from a 500 W Xe lamp); when the concentration of isothiazolone wastewater increased to 141 mg·L^-1, 77%~80% of isothiazolone could be removed. The optimum reaction time was 4 h. The analysis of photoreaction metabolites indicated that MI was the major residual substance at the end of photocatatlytic reaction; CMI was degraded to chloride and MI. At the same time, another unknown intermediate was found after the degradation of isothiazolone.