title: Simulation and comparative study on the oxidation kinetics of atrazine by UV/H₂O₂, UV/HSO₅⁻ and UV/S₂O₈²⁻.
abstract: This study comparatively investigated atrazine (ATZ) degradation by irradiation at the wavelength of 254 nm in the presence of peroxides including hydrogen peroxide (H2O2), peroxymonosulfate (HSO5(-)), and persulfate (S2O8(2-)) at various initial ATZ concentrations and oxidant dosages. The effects of water matrix, such as carbonate/bicarbonate (HCO3(-)/CO3(2-)), chloride ions (Cl(-)), and natural organic matter (NOM), were evaluated on these three advanced oxidation processes. A simple steady-state kinetic model was developed based on the initial rates of ATZ destruction, which could well describe the apparent pseudo-first-order rate constants (k(app), s(-1)) of ATZ degradation in these three processes. The specific roles of reactive species (i.e., HO·, SO4(-·), CO3(-·), and Cl2(-·)) under various experimental conditions were quantitatively evaluated based on their steady-state concentrations obtained from this model. Modeling results showed that the steady-state concentrations of HO· and SO4(-·) decreased with the increase of CO3(2-)/HCO3(-) concentration, and the relative contribution of HO· to ATZ degradation significantly decreased in UV/H2O2 and UV/HSO5(-) systems. On the other hand, the scavenging effect of HCO3(-)/CO3(2-) on the relative contribution of SO4(-·) to ATZ degradation was lower than that on HO·. The presence of Cl(-) (0.5-10 mM) significantly scavenged SO4(-·) but had slightly scavenging effect on HO· at the present experimental pH, resulting in greater decrease of k(app) in the UV/S2O8(2-) than UV/H2O2 and UV/HSO5(-) systems. Higher levels of Cl2(-·) were generated in the UV/S2O8(2-) than those in the UV/H2O2 and UV/HSO5(-) systems at the same Cl(-) concentrations. NOM significantly decreased k(app) due to its effects of competitive UV absorption and radical scavenging with the latter one being dominant. These results improve the understanding of the effects of water constituents for ATZ degradation in the UV-based oxidation processes.
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China.
authors.forename: Congwei
authors.initials: C
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China. Electronic address: majun@hit.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China. Electronic address: jiangjinhit@126.com.
authors.forename: Jin
authors.initials: J
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China.
authors.forename: Yongze
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Song
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.affiliation: School of Water Conservancy & Civil Engineering, Northeast Agricultural University, Harbin, 150030, China.
authors.forename: Yinghong
authors.initials: Y
authors.lastname: Guan
authors.affiliation: School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, 250010, China.
authors.forename: Daoji
authors.initials: D
authors.lastname: Wu
mesh_terms: D000465:Algorithms; D001280:Atrazine / Q000032:analysis / Q000737:chemistry*; D001639:Bicarbonates / Q000737:chemistry; D002254:Carbonates / Q000737:chemistry; D052918:Environmental Restoration and Remediation / Q000379:methods; D006861:Hydrogen Peroxide / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry; D007700:Kinetics; D008956:Models, Chemical; D010084:Oxidation-Reduction / Q000528:radiation effects; D010545:Peroxides / Q000737:chemistry*; D010782:Photolysis / Q000528:radiation effects; D013461:Sulfur Oxides / Q000737:chemistry*; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D001639:Bicarbonates; D002254:Carbonates; D010545:Peroxides; D013461:Sulfur Oxides; D014874:Water Pollutants, Chemical; C038288:peroxymonosulfate; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D001280:Atrazine
keywords: Atrazine; Hydroxyl radical; Steady-state kinetic model; Sulfate radical; UV-based oxidation