title: Iron-mediated oxidation of arsenic(III) by oxygen and hydrogen peroxide: dispersed versus resin-supported zero-valent iron.
abstract: The goal of this study is to assess the differences in As(III) removal kinetics and mechanisms between dispersed zero-valent iron (d-ZVI) and resin-supported zero-valent iron (D201-ZVI) in the presence of dissolved oxygen and hydrogen peroxide. Experimental results show that As(III) could be removed by all the studied systems (d-ZVI/O2, d-ZVI/H2O2, D201-ZVI/O2, D201-ZVI/H2O2). The d-ZVI/H2O2 system was more efficient than D201-ZVI/H2O2 for the oxidation of As(III). Similar trends were observed in O2 system for both solids. The kinetic behaviors as well as the influence of a hydroxyl radical scavenger (2-propanol) on the oxidation of As(III) at different pH suggest that the oxidation of As(III) in the d-ZVI/O2 and d-ZVI/H2O2 systems occurred mainly through Fenton-like reactions. The oxidation of As(III) in the D201-ZVI/O2 and D201-ZVI/H2O2 systems might be expected as follows: As(III) was firstly adsorbed onto the surface of the D201-ZVI, and then oxidation may proceed mainly through a non-Fenton mechanism that directly converts H2O2 into O2 and H2O. In addition, certain iron oxides in the D201-ZVI could also serve as oxidants for As(III) oxidation. The significant differences between the dispersed and supported ZVIs suggest that the supporting matrix interfered in the removal process, which deserves a further investigation.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Du
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China.
authors.forename: Lixia
authors.initials: L
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China. Electronic address: sjzhang@nju.edu.cn.
authors.forename: Shujuan
authors.initials: S
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China; National Engineering Center for Organic Pollution Control and Resource Reuse (Suzhou Division), Suzhou High-Tech Institute of Nanjing University, Suzhou 215123, PR China.
authors.forename: Bingcai
authors.initials: B
authors.lastname: Pan
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, PR China; National Engineering Center for Organic Pollution Control and Resource Reuse (Suzhou Division), Suzhou High-Tech Institute of Nanjing University, Suzhou 215123, PR 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, PR China; National Engineering Center for Organic Pollution Control and Resource Reuse (Suzhou Division), Suzhou High-Tech Institute of Nanjing University, Suzhou 215123, PR China. Electronic address: wmzhang@nju.edu.cn.
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, PR China.
authors.forename: Quanxing
authors.initials: Q
authors.lastname: Zhang
keywords: Arsenite; Hydrogen peroxide; Nano-ZVI; Oxidation; Polymeric resins