title: Effects of Mn(II) on the sorption and mobilization of As(V) in the presence of hematite.
abstract: In this study, the effects of Mn(II) on the sorption and mobilization of As(V) by synthetic hematite were investigated. Our results showed that As(V) removal by hematite was evidently dependent on pH, and simultaneous addition of Mn(II) and As(V) into hematite suspension resulted in more removal of As(V) via electrostatic attraction at pH 4.0, 7.0 and 8.3. However, in Mn(II) pre-loaded system, the removal percentages of As(V) at pH 8.3 decreased by 17.0%, 20.7% and 26.7% after 24h at the aging time of 2, 12 and 36 h, respectively. The concentrations of the released As(V) after the addition of 1mM Mn(II) were 23.6, 12.9 and 7.0 μM at pH 8.5 in 2, 3 and 4 g L(-1) hematite suspension, respectively. But Ca(2+) did not show such an effect under similar experimental conditions. Abiotic oxidation of Mn(II) on hematite played an important role in As(V) mobilization. The growing thin layer of Mn(III, IV) (hydr)oxides (MnO(x)) formed on hematite would take up the sorption sites pre-occupied by As(V) and resulted in the release of the adsorbed As(V) back into solution. This study enriched our understanding on As(V) fate in the coexistence of iron oxides and Mn(II).
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin, PR China.
authors.forename: Hai-Tao
authors.initials: HT
authors.lastname: Ren
authors.forename: Shao-Yi
authors.initials: SY
authors.lastname: Jia
authors.forename: Yong
authors.initials: Y
authors.lastname: Liu
authors.forename: Song-Hai
authors.initials: SH
authors.lastname: Wu
authors.forename: Xu
authors.initials: X
authors.lastname: Han
mesh_terms: D000327:Adsorption; D001151:Arsenic / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D055672:Static Electricity
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide; D008345:Manganese; D001151:Arsenic