蜂窝陶瓷催化臭氧化降解水中痕量硝基苯的机理研究 |
摘要点击 1886 全文点击 1643 投稿时间:2006-01-22 修订日期:2006-03-23 |
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中文关键词 蜂窝陶瓷 催化臭氧化 降解 硝基苯 机理 羟基自由基 抑制剂 |
英文关键词 ceramic honeycomb catalytic ozonation decomposition nitrobenzene mechanism hydroxyl radical inhibitor |
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中文摘要 |
实验考察了HCO-3、CO2-3 、HPO2-4、H2PO-4和叔丁醇等羟基自由基抑制剂存在条件下,单独臭氧氧化和臭氧/蜂窝陶瓷氧化对水中硝基苯降解效果的影响规律,初步推测了反应机理.结果表明,2种工艺对硝基苯的去除率都随着HCO-3浓度的增加(0~200 mg·L-1)先增高再降低,在浓度为50 mg·L-1时去除率达到最大值;单独臭氧氧化和臭氧/蜂窝陶瓷对硝基苯的去除率随着CO2-3浓度的增加(0~20 mg·L-1)分别降低了16.57%和27.52%,随着HPO2-4浓度的增加(0~12 mg·L-1)分别降低了13.61%和17.52%,随着H2PO-4浓度的增加(0~120 mg·L-1)分别降低了6.61%和12.52%,随着叔丁醇浓度的增加(0~10 mg·L-1)硝基苯去除率降低了30.06%和46.09%.证明单独臭氧氧化和臭氧/蜂窝陶瓷氧化对硝基苯的降解遵循·OH氧化机理,叔丁醇更适合作为自由基抑制剂用来推断单独臭氧氧化和臭氧/蜂窝陶瓷氧化降解硝基苯的反应机理.单独臭氧氧化对硝基苯的去除率随着pH值的升高(3.02~10.96)而增大,臭氧/蜂窝陶瓷氧化对硝基苯的去除率在pH=9.23时达到最大值. |
英文摘要 |
The experiment investigated effects of the presence of hydroxyl radical inhibitor on degradation efficiency of trace nitrobenzene in aqueous solution in the processes of ozonation alone and ceramic honeycomb-catalyzed ozonation, including HCO-3、CO2-3、HPO2-4、H2PO-4 and tert-butanol, and studied preliminarily on their mechanism. The results indicated that degradation rate of the two processes both increased firstly and decreased subsequently with the increase of the concentration of HCO-3 (0~200 mg·L-1), and reached the climax at the concentration of bicarbonate ion 50 mg·L-1 under the same experimental condition. The degradation rates of ozonation alone and ozonation/ceramic honeycomb both declined by 16.57% and 27.52% with the increase of the concentration of CO2-3 (0~20 mg·L-1), respectively, and decreased by 13.61% and 17.52% with the addition of the concentration of HPO2-4 (0~12 mg·L-1), and reduced by 6.61% and 12.52% with the enhancement of the concentration of H2PO-4 (0~120 mg·L-1), and dropped by 30.06% and 46.09% with the increasing of the concentration of tert-butanol (0~10 mg·L-1). The experimental results indicated that decomposition of nitrobenzene in both processes all followed the mechanism of oxidization by OH free radical, and tert-butanol is a more suitable indicator for the radical type reaction. The removal rate of ozonation alone rose with the increase of the concentration of pH (3.02~10.96), but that of ozonation/ceramic honeycomb process reached the maximum at pH=9.23. |