title: Enhanced decomposition of 1,4-dioxane in water by ozonation under alkaline condition.
abstract: 1,4-Dioxane is a probable human carcinogenic and refractory substance that is widely detected in aquatic environments. Traditional wastewater treatment processes, including activated sludge, cannot remove 1,4-dioxane. Removing 1,4-dioxane with a reaction kinetic constant of 0.32 L/(mol·s) by using ozone, a strong oxidant, is difficult. However, under alkaline environment, ozone generates a hydroxyl radical (•OH) that exhibits strong oxidative potential. Thus, the ozonation of 1,4-dioxane in water under different pH conditions was investigated in this study. In neutral solution, with an inlet ozone feed rate of 0.19 mmol/(L·min), the removal efficiency of 1,4-dioxane was 7.6% at 0.5 h, whereas that in alkaline solution was higher (16.3-94.5%) within a pH range of 9-12. However, the removal efficiency of dissolved organic carbon was considerably lower than that of 1,4-dioxane. This result indicates that several persistent intermediates were generated during 1,4-dioxane ozonation. The pseudo first-order reaction further depicted the reaction of 1,4-dioxane. The obvious kinetic constants (kobs) at pH 9, 10, 11 and 12 were 0.94, 2.41, 24.88 and 2610 L/(mol·s), respectively. Scavenger experiments on radical species indicated that •OH played a key role in removing 1,4-dioxane during ozonation under alkaline condition.
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, and State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China and Shenzhen Laboratory of Microorganism Application and Risk Control, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China E-mail: wuqianyuan@mail.tsinghua.edu.cn.
authors.forename: Gui-Peng
authors.initials: GP
authors.lastname: Tian
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, and State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China and Shenzhen Laboratory of Microorganism Application and Risk Control, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China E-mail: wuqianyuan@mail.tsinghua.edu.cn.
authors.forename: Qian-Yuan
authors.initials: QY
authors.lastname: Wu
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, and State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China and Shenzhen Laboratory of Microorganism Application and Risk Control, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China E-mail: wuqianyuan@mail.tsinghua.edu.cn.
authors.forename: Ang
authors.initials: A
authors.lastname: Li
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, and State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China and Shenzhen Laboratory of Microorganism Application and Risk Control, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China E-mail: wuqianyuan@mail.tsinghua.edu.cn.
authors.forename: Wen-Long
authors.initials: WL
authors.lastname: Wang
authors.affiliation: Environmental Simulation and Pollution Control State Key Joint Laboratory, and State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China and Shenzhen Laboratory of Microorganism Application and Risk Control, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China E-mail: wuqianyuan@mail.tsinghua.edu.cn.
authors.forename: Hong-Ying
authors.initials: HY
authors.lastname: Hu
mesh_terms: D004146:Dioxanes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical; D007700:Kinetics; D016877:Oxidants; D010084:Oxidation-Reduction; D010126:Ozone / Q000737:chemistry*; D062065:Wastewater; D014867:Water; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification
chemical_list: D004146:Dioxanes; D017665:Hydroxyl Radical; D016877:Oxidants; D010126:Ozone; D062065:Wastewater; D014867:Water; D014874:Water Pollutants, Chemical; C025223:1,4-dioxane