硅胶负载纳米TiO_2催化臭氧化降解水中微量硝基苯的研究  

Degradation of trace nitrobenzene by nano-TiO_2/silica-gel catalyzed ozonation in aqueous solution

作　　者：杨忆新[1] 马军[1] 张静[1] 王胜军[1] 秦庆东[1] 

机构地区：[1]哈尔滨工业大学市政环境工程学院,哈尔滨150090

出　　处：《环境科学学报》2006年第8期1258-1264,共7页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金资助项目(No.50378028)~~

摘　　要：研究了纳米TiO2负载于硅胶表面作为臭氧氧化硝基苯过程中的催化剂时,热处理温度对催化活性的影响.结果表明,在700℃条件下烧结的纳米TiO2/硅胶表现出了最佳活性,反应10min硝基苯去除率相比于单独臭氧氧化提高了约25%.在一定范围内催化剂投量越大,硝基苯去除率越高.碱性pH环境有利于催化臭氧化反应的进行,但当pH值高于10时,硝基苯去除率有所降低.催化臭氧化反应遵循一级反应,反应速率常数与硝基苯的初始浓度无关.典型的自由基捕获剂叔丁醇与碳酸根离子对硝基苯的降解有强烈的抑制作用,间接地证明催化臭氧化反应遵循自由基作用机理.反应温度为10～40℃之间时,硝基苯去除率随着温度升高而提高.催化剂重复使用实验证明TiO2在硅胶表面负载牢固,催化剂具有较好的稳定性与耐用性.In this paper nano-TiO2/Siliea-gel catalyzed ozonation of nitrobenzene was investigated. The best calcinations temperature was 700℃： for catalyst. The presence of nano-TiO2/Silica-gel increased the nitrobenzene removal rate by 25% than ozonation alone. Catalyst amount exerted a positive influence on nitrobenzene removal, and nitrobenzene degraded more completely under basic circumstances. Catalytic ozonation reaction was first order with no respect to the initial concentration of nitrobenzene. Two kinds of radical scavengers, t-butanol and carbonate, significantly influenced the degradation of nitrobenzene, which verified that nano-TiO2/Silica-gel catalyzed ozonation of nitrobenzene follows a radical-type mechanism. An increase of temperature from 10 to 40℃ yielded an increase at the removal rate of nitrobenzene. Repeated uses of catalyst did not decrease the nitrobenzene removal rate.

关 键 词：催化臭氧化 纳米二氧化钛 硅胶 负载 硝基苯 羟基自由基 

分 类 号：X703.1[环境科学与工程—环境工程]