以二氧化钛为代表的光催化能使许多有毒的有机污染物发生降解或矿化,产生易被生物降解的小分子和二氧化碳,过程涉及羟基自由基等活性物种。本文在作者小组的工作基础上,试图总结近年来二氧化钛、(羟基)氧化铁、杂多酸和金属酞菁光催化或光敏化在水处理方面所取得的研究进展。综述的重点是二氧化钛半导体光催化,讨论的内容包括:(1)超氧自由基、羟基自由基和单线态氧的检测和各种生成机理;(2)金属离子、杂多酸和氟离子修饰催化剂表面对活性物种产生的影响和可能机理;(3)离子交换树脂和有机膨润土负载金属酞菁对吸附和可见光敏化降解水中有机物的影响。
Photocatatysis as represented by titanium dioxide can make many toxic organic pollutants degraded or mineralized into biogradable small molecules or carbon dioxide, the process involving active species such as hydroxyl radicals. This article, based on the author's group work, attempts to outline the recent development in photocatalysis or photosenstiztation of titanium dioxide, iron (hydr)oxides, polyoxometalates (POM) and metal phthalocyanines (MPc) for water treatment. The emphasis is put on the semiconductor photocatalysis by titanium dioxide. The discussion includes: ( 1 ) detection of singlet oxygen, hydroxyl and superoxide radicals, and various mechanisms proposed for their formation, (2) surface modification of catalyst with metal ions, POM and fluoride ions, and possible mechansims for their effects on the production of reactive species, and (3) immobilization of MPc onto ionic exchange resin and organoclay, and the influence on sorption and visible light induced degradation of organic pollutants in aqueous medium.