Shewanella oneidensis MR-1异化铁还原诱导次生矿物固定镉

童昆; 徐成; 吴峥; 司友斌

文章摘要

童昆,徐成,吴峥,司友斌.Shewanella oneidensis MR-1异化铁还原诱导次生矿物固定镉[J].农业环境科学学报,2021,40(10):2114-2123.

Shewanella oneidensis MR-1异化铁还原诱导次生矿物固定镉

Immobilization of cadmium on secondary minerals induced by Shewanella oneidensis MR-1 through dissimilar iron reduction

投稿时间：2021-04-25

DOI：10.11654/jaes.2021-0496

中文关键词: Shewanella oneidensis MR-1 异化铁还原次生矿物镉固化稳定化

英文关键词: Shewanella oneidensis MR-1 dissimilatory iron reduction secondary mineral cadmium immobilization

基金项目:国家重点研发计划项目（2019YFC1805203）；国家自然科学基金项目（42077123）；安徽高校协同创新项目（GXXT-2021-061）

作者	单位	E-mail
童昆	农田生态保育与污染防控安徽省重点实验室, 安徽农业大学资源与环境学院, 合肥 230036
徐成	农田生态保育与污染防控安徽省重点实验室, 安徽农业大学资源与环境学院, 合肥 230036
吴峥	农田生态保育与污染防控安徽省重点实验室, 安徽农业大学资源与环境学院, 合肥 230036
司友斌	农田生态保育与污染防控安徽省重点实验室, 安徽农业大学资源与环境学院, 合肥 230036	youbinsi@ahau.edu.cn

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中文摘要:

实验室纯培养条件下，研究菌株Shewanella oneidensis MR-1还原铁矿物诱导次生矿物对Cd²⁺的固定，探讨pH、富里酸、生物炭对微生物还原水铁矿及其Cd²⁺固定的影响，并通过X射线衍射（XRD）、X射线光电子能谱（XPS）对次生矿物进行表征。结果表明： S.oneidensis MR-1异化铁还原诱导次生铁矿固定Cd²⁺的效果显著高于铁矿物自身的吸附，288 h未接种S.oneidensisMR-1和接种S.oneidensis MR-1的水铁矿溶液中Cd²⁺的浓度分别为2.71 mg·L^-1与0.86 mg·L^-1；酸性条件（pH≥5.0）及添加富里酸可促进铁矿物还原溶解和次生矿物转化，进而增强Cd²⁺的固定；添加生物炭提供了微生物定殖场所，虽减缓铁矿物还原的Fe²⁺溶出，但显著提高Cd²⁺的固定效果。铁氧化物矿物作为电子受体被微生物还原产生次生铁矿，其晶型结构改变与高表面积提供了更多的吸附点位，增强了Cd²⁺的固定。研究表明，次生铁矿物形成过程影响重金属的迁移转化及归宿，S.oneidensis MR-1还原铁矿物诱导产生次生铁矿可以有效固定Cd²⁺。

英文摘要:

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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