title: Mechanism for enhanced degradation of clofibric acid in aqueous by catalytic ozonation over MnOx/SBA-15.
abstract: Comparative experiments were conducted to investigate the catalytic ability of MnO(x)/SBA-15 for the ozonation of clofibric acid (CA) and its reaction mechanism. Compared with ozonation alone, the degradation of CA was barely enhanced, while the removal of TOC was significantly improved by catalytic ozonation (O3/MnO(x)/SBA-15). Adsorption of CA and its intermediates by MnO(x)/SBA-15 was proved unimportant in O3/MnO(x)/SBA-15 due to the insignificant adsorption of CA and little TOC variation after ceasing ozone in stopped-flow experiment. The more remarkably inhibition effect of sodium bisulfite (NaHSO3) on the removal of TOC in catalytic ozonation than in ozonation alone elucidated that MnO(x)/SBA-15 facilitated the generation of hydroxyl radicals (OH), which was further verified by electron spin-resonance spectroscopy (ESR). Highly dispersed MnO(x) on SBA-15 were believed to be the main active component in MnO(x)/SBA-15. Some intermediates were indentified and different degradation routes of CA were proposed in both ozonation alone and catalytic ozonation. The amounts of small molecular carboxylic acids (i.e., formic acid (FA), acetic acid (AA) and oxalic acid (OA)) generated in catalytic ozonation were lower than in ozonation alone, resulting from the generation of more OH.
authors.affiliation: School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China.
authors.forename: Qiangqiang
authors.initials: Q
authors.lastname: Sun
authors.affiliation: School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China. Electronic address: llsh@scnu.edu.cn.
authors.forename: Laisheng
authors.initials: L
authors.lastname: Li
authors.affiliation: Key Laboratory of Aquatic Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Jishuai
authors.initials: J
authors.lastname: Bing
authors.affiliation: School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China.
authors.forename: Yingxin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Chemistry & Environment, South China Normal University, Guangzhou 510006, China.
authors.forename: Huihua
authors.initials: H
authors.lastname: Yan
mesh_terms: D000327:Adsorption; D002384:Catalysis; D002995:Clofibric Acid / Q000032:analysis* / Q000737:chemistry; D017895:Manganese Compounds / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D010126:Ozone / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
chemical_list: D017895:Manganese Compounds; D010087:Oxides; C509969:SBA-15; D014874:Water Pollutants, Chemical; D002995:Clofibric Acid; C027424:manganese oxide; D010126:Ozone; D012822:Silicon Dioxide
keywords: Catalytic ozonation; Clofibric acid; Mineralization; MnO(x)/SBA-15; Reaction mechanism