Effect of pH on MnOx/GAC catalyzed ozonation for degradation of nitrobenzene
Effect of pH on MnOx/GAC catalyzed ozonation for degradation of nitrobenzene
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DOI：
10.1016/j.watres.2004.11.020
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发表时间：
2005-03-01
期刊：
影响因子：
12.8
通讯作者：
Guan, CY
中科院分区：
文献类型：
--
作者：
Ma, J;Sui, MH;Guan, CY
考察了pH值对MnOx/GAC多相催化臭氧化反应的影响。以硝基苯为模型难降解有机污染物。结果表明，在MnOx/GAC催化臭氧氧化中，低pH(2.74~3.52)条件下对硝基苯的降解效率高于高pH(6.72~9.61)条件下的降解率。这一结果不同于单独臭氧氧化的情况，在臭氧氧化的情况下，较高的pH对硝基苯的降解有积极的影响，因为产生了羟基自由基。在MnOx/GAC催化剂存在下，臭氧分解速度加快，较高的pH条件有利于臭氧分解。由于叔丁醇的存在对MnOx/GAC多相催化臭氧氧化没有任何影响，因此推测羟基自由基可能不是催化氧化中的主要活性物种。有机微污染物在MnOx/GAC催化剂上的吸附是一个重要步骤，直接影响催化氧化的效果。推测有机污染物可能在催化剂表面进一步分解。(C)2005爱思唯尔有限公司。保留所有权利。
The effect of pH on MnOx/GAC heterogeneous catalytic ozonation was investigated. Nitrobenzene was used as a model refractory organic pollutant. It was found that in MnOx/GAC catalytic ozonation, the degradation efficiency of nitrobenzene was higher under low pH conditions (pH 2.74-3.52) than that under high pH conditions (pH 6.72-9.61). This result was different from the case of ozonation alone, in which higher pH had positive effect on the degradation of nitrobenzene due to the formation of hydroxyl radical. In the presence of MnOx/GAC catalyst, ozone decomposition was accelerated, and higher pH condition favored ozone decomposition. It was assumed that hydroxyl radicals might not be the dominating active species in the catalytic oxidation, for the presence of t-butanol did not have any influence on MnOx/GAC heterogeneous catalytic ozonation. Adsorption of organic micropollutants on MnOx/GAC catalyst was an important step and would have direct influence on the effectiveness of catalytic oxidation. It was assumed that the organic pollutants might be further decomposed on the surface of catalyst. (c) 2005 Elsevier Ltd. All rights reserved.