不同光源下TiO_2膜对MC-RR光催化降解的比较研究  

Comparison of Various Lights in Photocatalytic Degradation of Microcystins (MC-RR) by TiO_2 Film

作　　者：陈晓国[1] 潘新朋[1] 杨红刚[1] 肖邦定[2] 徐小清[2] 

机构地区：[1]武汉理工大学资源环境学院,湖北武汉430070 [2]中国科学院水生生物研究所,湖北武汉430072

出　　处：《农业环境科学学报》2005年第1期46-49,共4页Journal of Agro-Environment Science

基　　金："973"资助项目(2002CB412300)

摘　　要：通过溶胶-凝胶法制备了纳米级的锐钛矿型TiO2膜,利用纯化的MC-RR分别研究了该膜在太阳光、UVA和UVC三种光源下对MC-RR的催化降解行为。结果表明,太阳光下TiO2膜对MC-RR的催化降解反应符合一级反应动力学,而在UVA和UVC下符合二级反应。不同光源下TiO2膜的催化效果差别较大,在太阳光下催化效果最为明显,反应速率常数由5.12×10-5·min-1增加到5.49×10-3·min-1,增加了两个数量级;UVA次之,由6.0×10-4L·mg-1·min-1增加到1.55×10-3L·mg-1·min-1,增加了1.6倍;而在UVC下,反应速率常数由3.2×10-2L·mg-1·min-1减小到1.98×10-2L·mg-1·min-1,减小了近38%,说明在UVC下TiO2膜具有抑制作用。尽管如此,MC-RR在UVC下的反应仍然是最快的,光照60min后降解率达到90.7%,其次是UVA,60min后降解率为49.5%,而太阳光下仅为31.2%。在应用TiO2膜光催化氧化法去除MC的过程中,应综合考虑能耗、水质指标以及设备投资等因素,选择合适的光源,以免降低MC的去除效率或增加能耗。Microcystins in drinking water pose a considerable threat to human health. Conventional water treatment systems are unreliable in removal of these toxins and hence new techniques are usually necessary for treatment of contaminated water. In this study, anatase TiO2 thin films deposited on glass have been prepared by sol-gel technology and the photocatalytic degradation of purified MC-RR was examined by exposure with sunlight, UVA and UVC, respectively. Our experimental results showed that the photocatalytic decomposition of MC-RR followed first order reaction kinetics by sunlight and second order reaction kineticsby UVA and UVC. The performances of TiO2 as photocatalyst were strongly dependent on light sources, and with the addition of TiO2 the reaction rate constants of MC-RR increased from 5.12×10-5min-1 to 5.49×10-3min-1 by sunlight, and from 6.0×10-4L·mg-1·min-1to 1.55×10-3 L·mg-1·min-1 by UVA, but decreased from 3.20×10-2L·mg-1·min-1to 1.98×10-2L·mg-1·min-1 by UVC. Even so, the decomposition rates of MC-RR by UVC was the rapidest with percentage removal of 90.7 %within 60 minutes, followed by UVA 49.5 %and sunlight 31.2 %. It is concluded that proper light source should be adopted to improve the efficiencies of treatment systems, when titanium dioxide films are used as photocatalyst for the removal of MC-RR from drinking water.

关 键 词：太阳光 UVA UVC 二氧化钛膜 光催化氧化 微囊藻毒素RR 

分 类 号：X122[环境科学与工程—环境科学]