Cr(Ⅵ)光催化还原

Photocatalytic Reduction of Cr( Ⅵ)

Cr(Ⅵ)是水体和土壤中普遍存在的重金属污染物,其处理方法有物理法﹑化学法和生物法等。光催化还原法是一种较理想的处理含Cr(Ⅵ)废水的高级化学方法。本文根据国内外含Cr(Ⅵ)废水处理时常用光催化剂的类别,对光催化技术处理废水中Cr(Ⅵ)的研究进行综述,分析了各类光催化剂的特点、优点、局限性,光催化还原Cr(Ⅵ)的机理,以及光催化过程中的协同效应。通过讨论认为,寻找高催化活性的新型光催化剂、拓展光催化剂的光响应范围、有效设计Cr(Ⅵ)与其他污染物同时光催化除去的混合体系、将光催化还原法与其他方法偶合等是未来光催化还原Cr(Ⅵ)及其实际应用的发展趋势。

Cr（VI） is one of the most widespread heavy-metal pollutants mainly from electroplating, metallurgy, textile, printing and dyeing, leather, ceramics, pharmaceuticals and other industries, existing widely in water and soil. The popular treatment methods of Cr（VI） in wastewater are physical, chemical, biological methods and so on. Photocatalytic reduction, as an advanced chemical method, is an ideal method for treating Cr（VI） in wastewater. This paper is focused on the research progress of photocatalytic reduction of Cr（VI） in wastewater both at home and abroad. According to the type of the photocatalysts, the advantages and disadvantages of the photocatalysts are analyzed, and the possible photocatalytic mechanisms are presented. The synergistic effect by adding photo-induced hole scavenger, mainly organic matters, is important and effective for improving the photocatalytic efficiency of Cr（VI） and economic and practical in real wastewater application. The trends of photocatalytie reduction methods are also pointed out. The developing directions of the photocatalysis are seeking catalysts with higher catalytic activity, expanding the light responding range of photocatalysts and effectively designing combined system including Cr（VI） and other pollutants which can be removed by photocatalysis simultaneously. Besides, composite catalysts made of two or more materials, and photocatalytic reduction coupled with other methods are also the trends for treating Cr（VI） in the future.