(1. 南华大学 污染控制与资源化技术湖南省高校重点实验室，衡阳 421001；
2. 南华大学 铀矿冶生物技术国防重点学科实验室，衡阳 421001)
摘 要: 采用现代分析方法探讨零价铁(ZVI)与奥奈达希瓦氏菌(S. oneidensis)MR-1还原U(Ⅵ)的效果与机制。结果表明：ZVI与S. oneidensis均能够还原U(Ⅵ)；在厌氧条件下，ZVI与S. oneidensis还原U(Ⅵ)存在协同作用。当pH为7、温度为30 ℃、U(Ⅵ)的初始浓度为20 mg/L、ZVI的投加量为1.0 g/L时，24 h S. oneidensis对U(Ⅵ)还原率达到96.9%；在0.5~2.0 g/L范围内，U(Ⅵ)的还原率随ZVI投量的增加而上升；在U(Ⅵ)初始浓度5.0~50.0 mg/L内，U(Ⅵ)的还原率与其浓度正相关。ZVI、Fe3O4和Fe2O3均能明显促进U(Ⅵ)的还原，而可溶态的Fe(Ⅲ)对U(Ⅵ)的还原具有明显的抑制作用。其他离子Cu2+、Ca2+、Mn2+和NO3-对U(Ⅵ)的还原存在抑制作用，以Cu2+的影响最大，Ca2+的影响次之，SO42-对U(Ⅵ)的还原影响较小。XPS分析结果表明，ZVI表面吸附和沉积了U(Ⅵ)和U(Ⅳ)两种价态的U元素，反应后的铀大部分形成了稳定的UO2。
关键字: 零价铁；U(Ⅵ)；奥奈达希瓦氏菌；XPS分析
（1. Hunan Provincial Key Laboratory of Pollution Control and Resources Reuse Technology,
University of South China, Hengyang 421001, China;
2. Key Discipline Laboratory for National Defence for Biotechnology in Uranium Mining and Hydrometallurgy,
University of South China, Hengyang 421001, China）
Abstract:The effects and mechanism of U(Ⅵ) reduction by Shewanella oneidensis (S.oneidensis) MR-1 with zero-valent iron(ZVI) were evaluated. The results show that either ZVI or bacteria can reduce U(Ⅵ) in the solution, and under anaerobic conditions, a cooperative action of ZVI and the bacteria S.oneidensis is observed in reducing process of U(Ⅵ). Under condition of pH 7.0, temperature 30 ℃, the initial concentration of U (Ⅵ) 20 mg/L and ZVI addition 1.0 g/L, the reduction rate of U(Ⅵ) reaches 96.9% by S.oneidensis reduction for 24 h. The reduction rate of U(Ⅵ) is improved with increasing amount of ZVI in the range of 0.5-2.0 g/L, and the reduction rate of U(Ⅵ) is positive correlated with its initial concentration in the range of 5.0-50.0 mg/L. Fe3O4, Fe2O3 and ZVI are effective accelerators for bioreduction of U(Ⅵ), and soluble Fe(Ⅲ) can remarkably inhibit U(Ⅵ) bioreduction. The other coexistence ions, such as Cu2+, Ca2+, Mn2+ and NO3-, show a remarkable negative effect on U(Ⅵ) reduction, and among these ions, the negative effect of Cu2+ is the greatest and that of Ca2+ is the second. SO42- has less influence on U(Ⅵ) bioreduction. XPS results indicate the deposition of U element are in forms of U(Ⅵ) and U(Ⅳ) on iron filings surface, and the reduction product U(Ⅳ) is most likely to be in the form of UO2.
Key words: zero-valent iron ( ZVI); U(Ⅵ); Shewanella oneidensis MR-1; XPS analysis
