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考察了在3种紫外光源(黑光灯、杀菌灯、臭氧灯)的照射下,分别以TiO2与Pd/TiO2为催化剂,甲酸降解过程中过氧化氢的生成机制.研究发现,在黑光灯/催化剂条件下,可在纯水中生成过氧化氢,但当催化剂缺失时几乎不能生成.在黑光灯或杀菌灯照射下,甲酸溶液在有催化剂存在时可被稳定分解,但当催化剂不存在时则分解非常缓慢.对各种光源而言,Pd/TiO2比TiO2催化降解甲酸的效果好.对光源条件的比较发现,甲酸分解速度与过氧化氢生成速度依次为臭氧灯>杀菌灯>黑光灯.结果表明,甲酸光催化分解初速度与过氧化氢生成的初速度呈正比,过氧化氢生成是光催化降解有机物的关键因素.
The mechanism of the formation of hydrogen peroxide during formic acid degradation was investigated under the irradiation of three kinds of UV light sources (black light, germicidal light and ozone lamp) with TiO2 and Pd / TiO2 as catalysts, respectively. It was found that in the black light / catalyst Under the conditions, hydrogen peroxide can be generated in pure water, but almost can not be generated when the catalyst is lacking.Formic acid can be decomposed stably in the presence of a catalyst under the irradiation of a black light lamp or a germicidal lamp, but when the catalyst is absent, Decomposition is very slow.For a variety of light sources, Pd / TiO2 photocatalytic degradation of formic acid than the TiO2 effect.Compared to the light source conditions, the rate of formation of formic acid and hydrogen peroxide generation rate of ozone lamp> germicidal lamp> black light. The results show that the initial velocity of photocatalytic decomposition of formic acid is directly proportional to the initial velocity of hydrogen peroxide generation. Hydrogen peroxide generation is the key factor for the photocatalytic degradation of organic matter.