Zhao Bei, Chen Xin, Chen Hongliang, Zhang Linlin, Li Jiang, Guo Yadan, Liu Haiyan, Zhou Zhongkui, Ke Pingchao, Sun Zhanxue
China University of Geosciences (Beijing), Beijing 100083, China.
School of Water Resources and Environmental Engineering, East China University of Technology, Nanchang, Jiangxi, China.
Environ Res. 2023 Nov 15;237(Pt 2):116950. doi: 10.1016/j.envres.2023.116950. Epub 2023 Sep 1.
Uranium pollution in groundwater environment has become an important issue of global concern. In this study, a strain of Desulfovibrio desulfuricans was isolated from the tailings of acid heap leaching, and was shown to be able to remove uranium from water via biosorption, bio-reduction, passive biomineralization under uranium stress, and active metabolically dependent bioaccumulation. This research explored the effects of nutrients, pH, initial uranium and sulfate concentration on the functional groups, uranium valence, and crystal size and morphology of uranium immobilization products. Results showed that tetravalent and hexavalent phosphorus-containing uranium minerals was both formed. In sulfate-containing water where Desulfovibrio desulfuricans A3-21ZLL can grow, the sequestration of uranium by bio-reduction was significantly enhanced compared to that with no sulfate loading or no growth. Ungrown Desulfovibrio desulfuricans A3-21ZLL or dead ones released inorganic phosphate group in response to the stress of uranium, which associated with soluble uranyl ion to form insoluble uranium-containing precipitates. This study revealed the influence of hydrochemical conditions on the mineralogy characteristics and spatial distribution of microbial uranium immobilization products. This study is conducive to the long-term and stable bioremediation of groundwater in decommissioned uranium mining area.
地下水环境中的铀污染已成为全球关注的重要问题。在本研究中，从酸性堆浸尾矿中分离出一株脱硫脱硫弧菌，结果表明该菌株能够通过生物吸附、生物还原、铀胁迫下的被动生物矿化以及活跃的代谢依赖性生物积累从水中去除铀。本研究探讨了营养物质、pH值、初始铀浓度和硫酸盐浓度对铀固定产物的官能团、铀价态以及晶体尺寸和形态的影响。结果表明，四价和六价含磷铀矿物均有形成。在脱硫脱硫弧菌A3 - 21ZLL能够生长的含硫酸盐水中，与无硫酸盐添加或不生长的情况相比，生物还原对铀的螯合作用显著增强。未生长的脱硫脱硫弧菌A3 - 21ZLL或死亡的菌株会因铀胁迫而释放无机磷酸基团，该基团与可溶性铀酰离子结合形成不溶性含铀沉淀物。本研究揭示了水化学条件对微生物铀固定产物的矿物学特征和空间分布的影响。本研究有助于退役铀矿区地下水的长期稳定生物修复。
