title: Antimony oxidation and adsorption by in-situ formed biogenic Mn oxide and Fe-Mn oxides.
abstract: Antimony (Sb), which can be toxic at relatively low concentrations, may co-exist with Mn(II) and/or Fe(II) in some groundwater and surface water bodies. Here we investigated the potential oxidation and adsorption pathways of Sb (III and V) species in the presence of Mn(II) and Mn-oxidizing bacteria, with or without Fe(II). Batch experiments were conducted to determine the oxidation and adsorption characteristics of Sb species in the presence of biogenic Mn oxides (BMOs), which were formed in-situ via the oxidation of Mn(II) by a Mn-oxidizing bacterium (Pseudomonas sp. QJX-1). Results indicated that Sb(III) ions could be oxidized to Sb(V) ions by BMO, but only Sb(V) originating from Sb(III) oxidation was adsorbed effectively by BMO. Introduced Fe(II) was chemically oxidized to FeOOH, the precipitates of which mixed with BMO to form a new compound, biogenic Fe-Mn oxides (BFMO). The BMO part of the BFMO mainly oxidized and the FeOOH of the BFMO mainly adsorbed the Sb species. In aquatic solutions containing both As(III) and Sb(III), the BFMO that formed in-situ preferentially oxidized Sb over As but adsorbed As more efficiently. Chemical analysis and reverse transcription real-time polymerase chain reaction revealed that the presence of Fe(II), As(III) and Sb(III) accelerated the oxidation of Mn(II) but inhibited the activity of Mn-oxidizing bacteria. These results provide significant insights into the biogeochemical pathways of Sb, Mn(II) in aquatic ecosystems, with or without Fe(II).
authors.affiliation: Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: yhbai@rcees.ac.cn.
authors.forename: Yaohui
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: William A
authors.initials: WA
authors.lastname: Jefferson
authors.affiliation: Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Jinsong
authors.initials: J
authors.lastname: Liang
authors.affiliation: Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Yang
authors.affiliation: Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Jiuhui
authors.initials: J
authors.lastname: Qu
mesh_terms: D000327:Adsorption; D000965:Antimony / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry*; D008956:Models, Chemical; D010084:Oxidation-Reduction
chemical_list: D005290:Ferric Compounds; D017895:Manganese Compounds; D000965:Antimony
keywords: Antimony; Arsenic; Biogenic Fe–Mn oxides; Biogenic Mn oxide; Oxidation and adsorption