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| Immobilization of cadmium on secondary minerals induced by Shewanella oneidensis MR-1 through dissimilar iron reduction |
| Received:April 25, 2021 |
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| KeyWord:Shewanella oneidensis MR-1;dissimilatory iron reduction;secondary mineral;cadmium;immobilization |
| Author Name | Affiliation | E-mail | | TONG Kun | Anhui Province Key Laboratory of Farmland Ecological Conservation and Pollution Prevention, School of Resources and Environment, Anhui Agricultural University, Hefei 230036, China | | | XU Cheng | Anhui Province Key Laboratory of Farmland Ecological Conservation and Pollution Prevention, School of Resources and Environment, Anhui Agricultural University, Hefei 230036, China | | | WU Zheng | Anhui Province Key Laboratory of Farmland Ecological Conservation and Pollution Prevention, School of Resources and Environment, Anhui Agricultural University, Hefei 230036, China | | | SI Youbin | Anhui Province Key Laboratory of Farmland Ecological Conservation and Pollution Prevention, School of Resources and Environment, Anhui Agricultural University, Hefei 230036, China | youbinsi@ahau.edu.cn |
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| Abstract: |
| We studied the immobilization effect of cadmium on secondary minerals, which was induced by the iron reduction with Shewanella oneidensis MR-1 under pure-culture laboratory conditions. Further, we investigated the effects of pH, fulvic acid, and biochar on the bioreduction of ferrihydrite and the immobilization of Cd2+. Meanwhile, secondary minerals were characterized using X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS) analysis. Our results showed that the immobilization of cadmium on secondary minerals induced by S. oneidensis MR-1 was stronger than the adsorption of iron minerals itself, the concentrations of Cd2+ in the solution without S. oneidensis MR-1 and inoculate S. oneidensis MR-1 at 288 h were 2.71 mg·L-1 and 0.86 mg·L-1, respectively. Acidic conditions(pH ≥ 5.0) and the addition of fulvic acid promoted the reduction dissolution of iron minerals and the transformation of secondary minerals, thus enhancing the immobilization of cadmium. The addition of biochar provided a site for microbial colonization, which slowed the dissolution of Fe2+ that was reduced by iron minerals; however, it significantly improved the immobilization effect of Cd2+. Iron-oxide minerals act as electron acceptors and are reduced by microorganisms to produce secondary iron minerals, which provide more adsorption sites to immobilize Cd2+ by changing their crystalline form and providing a higher surface area. These results show that, the secondary iron mineralization directly influences the fate of heavy metals. Cd2+ is effectively immobilized on secondary iron minerals induced by the iron reduction with Shewanella oneidensis MR-1. |
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