Stimulation of Fe(II) Oxidation, Biogenic Lepidocrocite Formation, and Arsenic Immobilization by Pseudogulbenkiania Sp. Strain 2002

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• 作者：Wei Xiu ; Huaming Guo ; Jiaxing Shen ; Shuai Liu ; Susu Ding ; Weiguo Hou ; Jie Ma ; Hailiang Dong
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：June 21, 2016
• 年：2016
• 卷：50
• 期：12
• 页码：6449-6458
• 全文大小：617K
• 年卷期：0
• ISSN：1520-5851

文摘

An anaerobic nitrate-reducing Fe(II)-oxidizing bacterium, Pseudogulbenkiania sp. strain 2002, was used to investigate As immobilization by biogenic Fe oxyhydroxides under different initial molar ratios of Fe/As in solutions. Results showed that Fe(II) was effectively oxidized, mainly forming lepidocrocite, which immobilized more As(III) than As(V) without changing the redox state of As. When the initial Fe/As ratios were kept constant, higher initial Fe(II) concentrations immobilized more As with higher As<sub>immobilizedsub>/Fe<sub>precipitatedsub> in biogenic lepidocrocite. EXAFS analysis showed that variations of initial Fe(II) concentrations did not change the As–Fe complexes (bidentate binuclear complexes (<sup>2sup>C)) with a fixed As(III) or As(V) initial concentration of 13.3 μM. On the other hand, variations in initial As concentrations but fixed Fe(II) initial concentration induced the co-occurrence of bidentate binuclear and bidentate mononuclear complexes (<sup>2sup>E) and bidentate binuclear and monodentate mononuclear complexes (<sup>1sup>V) for As(III) and As(V)-treated series, respectively. The coexistence of <sup>2sup>C and <sup>2sup>E complexes (or <sup>2sup>C and <sup>1sup>V complexes) could contribute to higher As removal in experimental series with higher initial Fe(II) concentrations at the same initial Fe/As ratio. Simultaneous removal of soluble As and nitrate by anaerobic nitrate-reducing Fe(II)-oxidizing bacteria provides a feasible approach for in situ remediation of As-nitrate cocontaminated groundwater.