title: Highly efficient and environmentally benign As(III) pre-oxidation in water by using a solid redox polymer.
abstract: As(III) preoxidation to As(V) is usually a requisite step for its efficient removal from water. Traditional oxidants reacting with As(III) homogenously in water suffer from the excessive dosage as well as the possible formation of disinfection byproducts. Herein, we developed a heterogeneous oxidant, i.e., a solid redox polymer (DOX), by covalently binding chlorine to a commercially available cation-exchange resin, D001. As(III) pre-oxidation by DOX is independent upon the solution pH (6-8) and ionic strength (0-0.1 M NaNO3). The presence of natural organic matters (NOMs) exhibits slightly adverse effect on the As(III) oxidation. More attractively, much less disinfection byproducts (DBPs, CHCl3in this study) is formed during oxidation by DOX than by chlorine, possibly ascribed to the electrostatic repulsion between NOMs and DOX as well as the steric effect of the solid matrix. The exhausted DOX could be fully refreshed by the NaClO solution for cyclic use. The column oxidation experiment were performed by feeding the synthetic groundwater containing As(III), various minerals, and NOMs. It could result in As(III) decline from 200 × 10-3mg/L initially to <1 × 10-3mg/L with the working capacity of >33,200 bed volume (BV) even at the volumetric flow rate of 50 BV/h (i.e., EBCT = 1.2 min, equivalent to the linear velocity of 2.2 m/h). In summary, DOX is a highly efficient and environmental friendly oxidant for As(III) pre-oxidation in water treatment.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
authors.forename: Hongchao
authors.initials: H
authors.lastname: Li
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
authors.forename: Mengfei
authors.initials: M
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
authors.forename: Weiming
authors.initials: W
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Lv
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China. Electronic address: bcpan@nju.edu.cn.
authors.forename: Bingcai
authors.initials: B
authors.lastname: Pan
mesh_terms: D001151:Arsenic / Q000737:chemistry*; D002713:Chlorine / Q000737:chemistry*; D016877:Oxidants / Q000737:chemistry*; D010084:Oxidation-Reduction; D011108:Polymers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D016877:Oxidants; D011108:Polymers; D014874:Water Pollutants, Chemical; D002713:Chlorine; D001151:Arsenic
keywords: Active chlorine; As(III); DBPs; Heterogeneous oxidation; Regeneration