title: Reductive dissolution of ferrihydrite with the release of As(V) in the presence of dissolved S(-II).
abstract: In this study, reductive dissolution of As(V)-ferrihydrite and the mobilization of As(V) in the presence of S(-II) were investigated under anoxic conditions. Mobilization of As(V) strongly depended on the S(-II):Fe ratio and the amount of As(V) loading on ferrihydrite. High S(-II):Fe ratio caused a more complete dissolution of ferrihydrite and a large fraction of As(V) could be released into solution. The percentages of the released As(V) were 2.5% and 7.5% at S(-II):Fe ratios of 0.240 and 24.0, respectively, at pH 6.1, while the released As(V) were 5.5%, 16.3% at pH 8.0 under similar conditions. As(V) loading showed a negative effect on the release of arsenate, with smaller fraction of arsenate released into solution when more As (V) adsorbed on ferrihydrite. After 43 h, 14.1%, 5.5%, 1.6% and 0.7% of As(V) were released as for 10, 20, 50 and 100 mg L(-1) of As(V) loading, respectively, at pH 8.0. During the dissolution, secondary minerals such as goethite, magnetite and FeS were detected and played different roles in the mobilization of As(V). The released As(V) was mainly repartitioned on the residual ferrihydrite, the newly-formed goethite and magnetite but not FeS.
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin, PR China.
authors.forename: Fu-Gen
authors.initials: FG
authors.lastname: Huang
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin, PR China.
authors.forename: Shao-Yi
authors.initials: SY
authors.lastname: Jia
authors.affiliation: School of Chemistry and Chemical Engineering, Tianjin University of Technology, Tianjin, PR China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin, PR China.
authors.forename: Song-Hai
authors.initials: SH
authors.lastname: Wu
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin, PR China; Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin 300072, PR China. Electronic address: xuhan@tju.edu.cn.
authors.forename: Xu
authors.initials: X
authors.lastname: Han
mesh_terms: D001149:Arsenates / Q000032:analysis*; D005290:Ferric Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D046529:Microscopy, Electron, Transmission; D010084:Oxidation-Reduction; D012995:Solubility; D013440:Sulfides / Q000737:chemistry*; D013499:Surface Properties; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D001149:Arsenates; D005290:Ferric Compounds; D013440:Sulfides; D014874:Water Pollutants, Chemical; C092844:ferric oxyhydroxide
keywords: Arsenate; As(V) loading; Ferrihydrite; Mobilization; S(-II):Fe ratio