title: Effects of common dissolved anions on the reduction of para-chloronitrobenzene by zero-valent iron in groundwater.
abstract: Batch tests were conducted to evaluate the influences of several common dissolved anions in groundwater on the reduction of para-chloronitrobenzene (p-CNB) by zero-valent iron (ZVI). The results showed that p-CNB reduction was enhanced by both Cl(-) and SO(4)(2-). HCO(3)(-) could either improve or inhibit p-CNB reduction, depending on whether the mixing speed was intense enough to rapidly eliminate Fe-carbonate complex deposited on ZVI surface. Above a concentration of 100 mg L(-1), NO(3)(-) increased the p-CNB reduction rate. The reduction rate by ClO(4)(-) decreased because the ClO(4)(-) competed with p-CNB for electrons. The p-CNB reduction was inhibited by PO(4)(3-), SiO(3)(2-) and humic acid, in the order humic acid < PO(4)(3-) < SiO(3)(2-), since these ions could form inner-sphere complexes on iron surface. The reaction even ceased when the ion concentrations were greater than 4, 0.5, and 30 mg L(-1), respectively. The results indicated that common dissolved anions in groundwater should be taken into account when ZVI is applied for contaminated groundwater remediation.
authors.affiliation: School of Environmental Science and Engineering, South China University of Technology, Guangzhou 510006, China. le.c@mail.scut.edu.cn
authors.forename: C
authors.initials: C
authors.lastname: Le
authors.forename: J H
authors.initials: JH
authors.lastname: Wu
authors.forename: S B
authors.initials: SB
authors.lastname: Deng
authors.forename: P
authors.initials: P
authors.lastname: Li
authors.forename: X D
authors.initials: XD
authors.lastname: Wang
authors.forename: N W
authors.initials: NW
authors.lastname: Zhu
authors.forename: P X
authors.initials: PX
authors.lastname: Wu
mesh_terms: D000838:Anions / Q000737:chemistry*; D006812:Humic Substances; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D009578:Nitrobenzenes / Q000737:chemistry*; D010084:Oxidation-Reduction; D014877:Water Pollution, Chemical / Q000517:prevention & control*; D018508:Water Purification / Q000379:methods; D014881:Water Supply
chemical_list: D000838:Anions; D006812:Humic Substances; D009578:Nitrobenzenes; C010407:4-chloronitrobenzene; D007501:Iron