Zuo Guo-Min, Cheng Zhen-Xing, Chen Hong, Li Guo-Wen, Miao Ting
The No. 3 Department, Institute of Chemical Defence, P.O. Box 1048, Beijing 102205, China.
J Hazard Mater. 2006 Feb 6;128(2-3):158-63. doi: 10.1016/j.jhazmat.2005.07.056. Epub 2005 Sep 12.
The gas-phase photolytic and photocatalytic reactions of several aromatics and chlorohydrocarbons were investigated. The experimental results revealed that chlorohydrocarbons like trichloroethylene, dichloromethane and chloroform could be degraded through either photolysis or photocatalysis under irradiation of germicidal lamp, and the elimination rate of chlorohydrocarbons through photolysis was quicker than that through photocatalysis. UV light from a germicidal lamp could directly lead to degradation of toluene but could hardly act on benzene. The photodegradation rate for these volatile organic compounds (VOCs) through photolysis followed an order: trichloroethylene>chloroform>dichloromethane>toluene>benzene>carbon tetrachloride, and through photocatalysis followed: trichloroethylene>chloroform>toluene>dichloromethane>benzene>carbon tetrachloride. Besides, a series of modified TiO2 photocatalysts were prepared by depositing noble metal, doping with transition metal ion, recombining with metal oxides and modifying with super strong acid. Activity of these catalysts was examined upon photocatalytic degradation of benzene as a typical compound that was hard to be degraded. It indicated that these modification methods could promote the activity of TiO2 catalyst to different extent. The apparent zero-order reaction rate constant for degrading benzene over SnO2/TiO2 catalyst had the highest value, which was nearly three times as that over P25 TiO2. But it simultaneously had the lowest rate for mineralizing the objective compound. In spite that Fe3+/TiO2 catalyst behaved slightly less active than SnO2/TiO2 for degradation of benzene, the mineralization rate over Fe3+/TiO2 was the highest one among the prepared catalysts.
研究了几种芳烃和氯代烃的气相光解和光催化反应。实验结果表明，三氯乙烯、二氯甲烷和氯仿等氯代烃在杀菌灯照射下可通过光解或光催化降解，且氯代烃的光解消除速率比光催化快。杀菌灯发出的紫外光可直接导致甲苯降解，但对苯几乎不起作用。这些挥发性有机化合物（VOCs）的光解光降解速率顺序为：三氯乙烯>氯仿>二氯甲烷>甲苯>苯>四氯化碳，光催化降解速率顺序为：三氯乙烯>氯仿>甲苯>二氯甲烷>苯>四氯化碳。此外，通过沉积贵金属、掺杂过渡金属离子、与金属氧化物复合以及用超强酸改性等方法制备了一系列改性TiO₂光催化剂，并以苯这种难降解的典型化合物为对象考察了这些催化剂的光催化降解活性。结果表明，这些改性方法能不同程度地提高TiO₂催化剂的活性。在SnO₂/TiO₂催化剂上降解苯的表观零级反应速率常数最高，几乎是P25 TiO₂的三倍。但同时其目标化合物矿化速率最低。尽管Fe³⁺/TiO₂催化剂对苯的降解活性略低于SnO₂/TiO₂，但在制备的催化剂中，Fe³⁺/TiO₂的矿化速率最高。
