Dependence of bisphenol A photodegradation on the initial concentration of oxalate in the lepidocrocite-oxalate complex system  

作　　者：DONG Jun LI Fang-bai LAN Chong-yu LIU Cheng-shuai LI Xiao-min LUAN Tian-gang 

机构地区：[1]School of Life Science, Sun Yat-sen University, Guangzhou 510275, China [2]Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environment and Soil Science, Guangzhou 510650, China [3]Zhongshan Institute, University of Electronic Science and Technology of China, Zhongshan 528402, China

出　　处：《Journal of Environmental Sciences》2006年第4期777-782,共6页环境科学学报（英文版）

基　　金：TheNationalNaturalScienceFoundationofChina(No.20377011),theZhongshanScienceProject(No.2003A030)andtheGuangdongNaturalScienceFoundation(No.036533)

摘　　要：To understand the degradation of endocrine disrupting chemicals （EDCs） in natural environment with existence of iron oxides and carboxylic acids, the dependence of bisphenol A （BPA） photodegradation on the initial concentration of oxalate （Cox） in lepidocrocite （y-FeOOH） aqueous suspension was investigated under both UV and visible lights in this study. Lepidocrocite powder was home-prepared by a hydrothermal process. It was found that BPA degradation was promoted greatly in the presence of oxalate owing to the formation of lepidocrocite-oxalate complex. And there was an optimal Cox, which was 2.0 and 2.4 mmol/L, under UV and visible lights, respectively. The first-order kinetic constant, k value increased 38 times from 0.17 × 10^-2 min^-1 in the absence of oxalate to 6.39 × 10^-2 min^-1 in the presence of oxalate with an optimal Cox （2.0 mmol/L） under UV irradiation, and almost 306 times from 0.02 × 10^-2 min^-1 in the absence of oxalate to 6.11 × 10^-2 min^-1 in the presence of oxalate with an optimal Cox （2.4 mmol/L） under visible irradiation. The BPA degradation rate increased and the first-order kinetic constants decreased with the increase in BPA initial concentration. The dependence of the variation of pH value, total-Fe and Fe^2＋ during the photoreaction on Cox was also investigated. The pH value increased obviously with the reaction time. Total-Fe increased dramatically at the first 5 min and then decreased quickly under UV irradiation and slowly under visible irradiation. The initial concentration of oxalate is a main factor to affect BPA photodegradation in aqueous suspension under both UV and visible lights.To understand the degradation of endocrine disrupting chemicals （EDCs） in natural environment with existence of iron oxides and carboxylic acids, the dependence of bisphenol A （BPA） photodegradation on the initial concentration of oxalate （Cox） in lepidocrocite （y-FeOOH） aqueous suspension was investigated under both UV and visible lights in this study. Lepidocrocite powder was home-prepared by a hydrothermal process. It was found that BPA degradation was promoted greatly in the presence of oxalate owing to the formation of lepidocrocite-oxalate complex. And there was an optimal Cox, which was 2.0 and 2.4 mmol/L, under UV and visible lights, respectively. The first-order kinetic constant, k value increased 38 times from 0.17 × 10^-2 min^-1 in the absence of oxalate to 6.39 × 10^-2 min^-1 in the presence of oxalate with an optimal Cox （2.0 mmol/L） under UV irradiation, and almost 306 times from 0.02 × 10^-2 min^-1 in the absence of oxalate to 6.11 × 10^-2 min^-1 in the presence of oxalate with an optimal Cox （2.4 mmol/L） under visible irradiation. The BPA degradation rate increased and the first-order kinetic constants decreased with the increase in BPA initial concentration. The dependence of the variation of pH value, total-Fe and Fe^2＋ during the photoreaction on Cox was also investigated. The pH value increased obviously with the reaction time. Total-Fe increased dramatically at the first 5 min and then decreased quickly under UV irradiation and slowly under visible irradiation. The initial concentration of oxalate is a main factor to affect BPA photodegradation in aqueous suspension under both UV and visible lights.

关 键 词：bisphenol A LEPIDOCROCITE OXALATE PHOTODEGRADATION 

分 类 号：X131[环境科学与工程—环境科学]