Abstract：
Immobilisation of uranium (U (VI)) by direct precipitation of uranyl phosphate (U-P) exhibits a great potential application in the remediation of U (VI)-contaminated environments. However, phosphorus, vital element of bacteria\'s decomposition, absorption and transformationmay affect the stability of U (VI) with ageing time. The main purpose of this work is to study the effect of bacteria on uranium sequestration mechanism and stability by different forms of phosphorus in a water sedimentary system. The results showed that phosphate effectively enhanced the removal of U (VI), with 99.84%. X-Ray Diffraction (XRD), Scanning Electron Microscopy and Energy Dispersive Spectrometer (SEM-EDS), and X-ray Photoelectron Spectroscopy (XPS) analyses imply that U (VI) and U (IV) co-exist on the surface of the samples. Combined with BCR results, it demonstrated that bacteria and phosphorus have a synergistic effect on the removal of U (VI), realising the immobilisation of U (VI) from a transferable phase to a stable phase. However, from a long-term perspective, the redissolution and release of uranium immobilisation of U (VI) by pure bacteria with ageing time are worthy of attention, especially in uranium mining environments rich in sensitive substances. This observation implies that the stability of the uranium may be impacted by the prevailing environmental conditions. The novel findings could provide theoretical evidence for U (VI) bio-immobilisation in U (VI)-contaminated environments.
摘要：
通过直接沉淀磷酸铀酰（U-P）固定铀（U（VI））在修复U（VI）污染的环境中具有巨大的潜在应用。然而,磷，细菌分解的重要元素，吸收和转化可能会影响U（VI）随老化时间的稳定性。这项工作的主要目的是研究细菌在水沉积体系中不同形式的磷对铀固存机理和稳定性的影响。结果表明，磷酸盐有效地增强了U（VI）的去除，99.84%。X射线衍射(XRD)扫描电子显微镜和能量色散光谱仪(SEM-EDS),和X射线光电子能谱(XPS)分析意味着U(VI)和U(IV)共存于样品表面。结合BCR结果，表明细菌和磷对U(VI)的去除具有协同作用，实现U（VI）从可转移阶段到稳定阶段的固定。然而,从长远来看,纯细菌对铀(VI)固定化的再溶解和释放随老化时间的变化值得关注,特别是在富含敏感物质的铀矿环境中。这一观察表明，铀的稳定性可能会受到当前环境条件的影响。新发现可以为U（VI）污染环境中的U（VI）生物固定提供理论证据。
