摘要
实验考察了HCO3^-、CO3^2-、HPO4^2-、H2PO4^-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HCO3^-浓度的增加(0-200mg·L^-1)先增高再降低,在浓度为50mg·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CO3^2-浓度的增加(0-20mg·L^-1)分别降低了16.57%和27.52%,随着HPO4^2-浓度的增加(0-12mg·L^-1)分别降低了13.61%和17.52%,随着H2PO4^-浓度的增加(0-120mg·L^-1)分别降低了6.61%和12.52%,随着叔丁醇浓度的增加(0-10mg·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.
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 HCO3^- , CO3^2- , HPO4^2- , H2PO4^- 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 HCO3^- (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 CO3^2- (0 - 20 mg·L^-1 ), respectively, and decreased by 13.61% and 17.52% with the addition of the concentration of HPO4^2- (0 - 12 mg·L^-1 ), and reduced by 6.61% and 12.52% with the enhancement of the concentration of H2PO4^- (0 - 120 mg·L^-1), and dropped by 30.06% and 46.09% with the increasing of the concentration of ten-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 ten-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.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2007年第2期335-341,共7页
Environmental Science
基金
国家自然科学基金项目(50378028)
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
ceramic honeycomb
catalytic ozonation
decomposition
nitrobenzene
mechanism
hydroxyl radical
inhibitor