title: Transformation of dissolved organic matter in concentrated leachate from nanofiltration during ozone-based oxidation processes (O3, O3/H2O2and O3/UV).
abstract: In this study, the transformation of dissolved organic matter (DOM) in nanofiltration concentrated leachate during three ozone-based oxidation processes (i.e., O3, O3/H2O2and O3/UV) was investigated. The transformation characteristics of DOM were evaluated by gel filtration chromatography (GFC), XAD-8 resin fractionation, excitation-emission matrix fluorescence spectroscopy (EEM) and Fourier transform infrared spectroscopy (FTIR). Compared with O3-alone process, the removal efficiencies of COD, TOC, and color were improved in O3-combined processes (i.e., O3/H2O2and O3/UV) approximately by 10-15%, 7-15%, and 15-20%, respectively. Humic acid (HA) was completely degraded and preferentially reacted with the oxidants during ozonation processes. HA was first converted into fulvic acid (FA), and then the majority of these intermediates were further converted to hydrophilic fraction (HyI). The GFC results indicated that the broader molecular weight distribution of DOM was observed, and high molecular weight DOM (i.e., 0.45 μm-100 kDa) was successfully converted to low molecular weight organics in the range of 1-10 kDa after ozonation reactions. The EEM spectra also showed that HA and FA were effectively converted into HyI after ozonation for 90 min. It is suggested that ozone-based oxidation processes could effectively change the DOM distribution and fluorescence features of concentrated leachate.
authors.affiliation: College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, PR China; Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, PR China.
authors.forename: Hua-Wei
authors.initials: HW
authors.lastname: Wang
authors.affiliation: College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, PR China.
authors.forename: Xiao-Yue
authors.initials: XY
authors.lastname: Li
authors.affiliation: College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, PR China.
authors.forename: Zhi-Peng
authors.initials: ZP
authors.lastname: Hao
authors.affiliation: College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, PR China.
authors.forename: Ying-Jie
authors.initials: YJ
authors.lastname: Sun
authors.affiliation: College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China. Electronic address: wangyanan1005@yeah.net.
authors.forename: Ya-Nan
authors.initials: YN
authors.lastname: Wang
authors.affiliation: College of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, PR China.
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Li
authors.affiliation: Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, New Territories, Hong Kong. Electronic address: tsangyf@eduhk.hk.
authors.forename: Yiu Fai
authors.initials: YF
authors.lastname: Tsang
mesh_terms: D002850:Chromatography, Gel; D006812:Humic Substances; D006861:Hydrogen Peroxide / Q000737:chemistry*; D010084:Oxidation-Reduction; D010126:Ozone / Q000737:chemistry*
chemical_list: D006812:Humic Substances; D010126:Ozone; D006861:Hydrogen Peroxide
keywords: Concentrated leachate; Dissolved organic matter; Nanofiltration; Ozone