title: Reductive dechlorination of carbon tetrachloride by bioreduction of nontronite.
abstract: Reductive dechlorination of carbon tetrachloride (CT) was investigated during bioreduction of iron-containing clay mineral (i.e., nontronite) by iron-reducing bacteria (Shewanella putrefaciens CN32 (CN32)). In the absence of CT, the production of Fe(II) significantly increased in nontronite suspension with CN32 in 124 d (11.1% of Fe(III) reduction), resulting in formation of new secondary Fe(II) mineral phase (i.e., vivianite (FeII3(PO4)2·8H2O)). In the presence of CT, an acceleration of CT dechlorination was observed after 13 d and it reached almost 68% of removal efficiency at 32 d in nontronite suspension with CN32, which was 1.8 times higher than that by CN32 alone (37%). Significant amounts of formate (30.1%) and CO (2.4%) were measured during the CT dechlorination in the nontronite suspension with CN32. Results obtained from Fe(II) measurement and X-ray diffraction (XRD) showed the acceleration of Fe(II) production after 13 d and the formation of vivianite in the range of 13-25 d, suggesting that the biogenic vivianite enhanced the CT dechlorination in this study. Experimental results from batch kinetic tests, Fe(II) measurements, XRD analysis, and by-product study suggested that the formation of vivianite can play a crucial role for the enhanced reductive dechlorination of CT in phosphorous enriched subsurface environments with iron-containing clay minerals.
authors.affiliation: Department of Environmental Engineering, College of Engineering, Konkuk University, Neungdong-ro 120, Gwangjin-gu, Seoul 05029, Republic of Korea.
authors.forename: Sungjun
authors.initials: S
authors.lastname: Bae
authors.affiliation: Department of Chemical Engineering, College of Engineering, Konkuk University, Neungdong-ro 120, Gwangjin-gu, Seoul 05029, Republic of Korea.
authors.forename: Ji Bong
authors.initials: JB
authors.lastname: Joo
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-ro, Nam-gu, Pohang 37673, Republic of Korea. Electronic address: woojin_lee@kaist.edu.
authors.forename: Woojin
authors.initials: W
authors.lastname: Lee
mesh_terms: D000538:Aluminum Silicates / Q000378:metabolism*; D002251:Carbon Tetrachloride / Q000378:metabolism*; D000077215:Clay; D005290:Ferric Compounds / Q000378:metabolism; D005296:Ferrous Compounds / Q000378:metabolism; D054879:Halogenation; D010084:Oxidation-Reduction; D020614:Shewanella putrefaciens / Q000378:metabolism*; D014961:X-Ray Diffraction
chemical_list: D000538:Aluminum Silicates; D005290:Ferric Compounds; D005296:Ferrous Compounds; D002251:Carbon Tetrachloride; D000077215:Clay
keywords: Carbon tetrachloride; Nontronite; Shewanella putrefaciens CN32; Vivianite