title: Fate of Fe and Cd upon microbial reduction of Cd-loaded polyferric flocs by Shewanella oneidensis MR-1.
abstract: Polyferric sulphate has been widely used for emergent control on incidental release of heavy metals such as Cd to surface water, causing precipitation of Cd-loaded polyferric flocs to the sediment. To date, little is known about whether the dissolution of the flocs in the presence of dissimilatory iron reducing bacteria (DIRB) can occur and how the dissolution influences the fate of Fe and Cd in the sediment. Here, we demonstrated that Shewanella oneidensis MR-1, as representative DIRB, has the ability to reduce the flocs, resulting in the release of Fe(2+) and Cd(2+) to the solution. Batch experiment results showed that the concentrations of Fe(2+) and Cd(2+)reached the maximum values at 48 h and then decreased over the remaining incubation time. The characterizations on the solid phase by the scanning electron microscopy coupled with energy dispersive spectrometer, X-ray diffraction, and X-ray photoelectron spectroscopy technologies revealed the formation of iron minerals such as goethite and magnetite as a consequence of microbial Fe(III) reduction. The newly formed iron minerals played a significant role in re-immobilizing Cd by sorption. These results imply that microbial reduction of polyferric flocs is an important contributor to the transport and transformation of metals in the sediment-water interface.
authors.affiliation: The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China.
authors.forename: Chenchen
authors.initials: C
authors.lastname: Li
authors.affiliation: The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China. Electronic address: xyyi@scut.edu.cn.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Yi
authors.affiliation: The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Dang
authors.affiliation: The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China.
authors.forename: Hui
authors.initials: H
authors.lastname: Yu
authors.affiliation: The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zeng
authors.affiliation: The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China.
authors.forename: Chaohai
authors.initials: C
authors.lastname: Wei
authors.affiliation: The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, PR China. Electronic address: chfeng@scut.edu.cn.
authors.forename: Chunhua
authors.initials: C
authors.lastname: Feng
mesh_terms: D002104:Cadmium / Q000737:chemistry / Q000378:metabolism*; D005290:Ferric Compounds / Q000737:chemistry / Q000378:metabolism*; D052203:Ferrosoferric Oxide / Q000737:chemistry; D005427:Flocculation; D007501:Iron / Q000737:chemistry / Q000378:metabolism*; D058085:Iron Compounds / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008903:Minerals / Q000737:chemistry; D010084:Oxidation-Reduction; D056951:Photoelectron Spectroscopy; D020592:Shewanella / Q000378:metabolism*; D014961:X-Ray Diffraction
chemical_list: D005290:Ferric Compounds; D058085:Iron Compounds; D008903:Minerals; D002104:Cadmium; C094886:goethite; C024823:ferric sulfate; D007501:Iron; D052203:Ferrosoferric Oxide
keywords: Cd adsorption; Coagulation; Dissimilatory iron reduction; Polyferric flocs; Secondary mineralization