Photocatalytic degradation of carbofuran in TiO_2 aqueous solution: Kinetics using design of experiments and mechanism by HPLC/MS/MS  

作　　者：Hai Yang Shuolin Zhou Huajie Liu Weiwei Yan Liping Yang Bing Yi 

机构地区：[1]College of Chemistry and Chemical Engineering, Hunan Institute of Engineering [2]College of Chemistry and Chemical Engineering, Hunan Normal University [3]South China Institute of Environmental Sciences, Ministry of Environmental Protection

出　　处：《Journal of Environmental Sciences》2013年第8期1680-1686,共7页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (No.21207034, 21172064);the Provincial Natural Science Foundation of Hunan (No.10JJ2006);the Key Scientific Research Fund of Hunan Provincial Education Department (No.10A022)

摘　　要：The photocatalytic degradation kinetics of carbofuran was optimized by central composite design based on response surface methodology for the first time. Three variables, TiO2 concentration, initial pH value and the concentration of carbofuran, were selected to determine the dependence of degradation efficiencies on independent variables. Response surface methodology modeling results indicated that the degradation efficiency of carbofuran was highly affected by the initial pH value and the concentration of carbofuran. Then nine degradation intermediates were detected by HPLC/MS/MS. The Frontier Electron Densities of carbofuran were calculated to predict the active sites on carbofuran attacked by hydroxyl radicals and photoholes. Point charges were used to elucidate the chemisorption pattern on TiO2 catalysts during the photocatalytic process. By combining the experimental results and calculation data, the photocatalytic degradation pathways of carbofuran were proposed, including the addition of hydroxyl radicals and the cleavage of the carbamate side chain.The photocatalytic degradation kinetics of carbofuran was optimized by central composite design based on response surface methodology for the first time. Three variables, TiO2 concentration, initial pH value and the concentration of carbofuran, were selected to determine the dependence of degradation efficiencies on independent variables. Response surface methodology modeling results indicated that the degradation efficiency of carbofuran was highly affected by the initial pH value and the concentration of carbofuran. Then nine degradation intermediates were detected by HPLC/MS/MS. The Frontier Electron Densities of carbofuran were calculated to predict the active sites on carbofuran attacked by hydroxyl radicals and photoholes. Point charges were used to elucidate the chemisorption pattern on TiO2 catalysts during the photocatalytic process. By combining the experimental results and calculation data, the photocatalytic degradation pathways of carbofuran were proposed, including the addition of hydroxyl radicals and the cleavage of the carbamate side chain.

关 键 词：CARBOFURAN photocatalytic degradation central composite design KINETICS MECHANISM 

分 类 号：X832[环境科学与工程—环境工程]