共存离子对ZVI/S.oneidensis还原U(Ⅵ)的影响研究

Influence of Coexistent Ions on Reduction of U(Ⅵ) by S. oneidensis with ZVI

研究零价铁(ZVI)与奥奈达希瓦氏菌(S.oneidensis)协同还原去除水相中U(Ⅵ)时,共存离子Cr^(6+)、Fe^(3+)、Cu^(2+)、Mn^(2+)、Zn^(2+)、NO_3^-和SO_4^(2-)分别存在时对U(Ⅵ)还原效果的影响。结果表明:溶液中共存的Cr^(6+)和溶解态的Fe^(3+)对ZVI与微生物协同还原U(Ⅵ)均存在显著的抑制作用,且当溶液中共存Cr^(6+)的含量超过10.0 mg/L时,U(Ⅵ)的还原几乎被完全抑制。在共存金属浓度为20 mg/L时,Cu^(2+)、Zn^(2+)对U(Ⅵ)的还原均具有抑制作用,且Cu^(2+)的影响大于Zn^(2+);Mn^(2+)对U(Ⅵ)的还原有微弱的促进作用。共存阴离子SO_4^(2-)对U(Ⅵ)的还原有微弱的促进作用,且作用大小与其浓度成正相关;在0.5~5.0 mmol/L浓度范围内,12 h时,共存阴离子NO_3^-对U(Ⅵ)的还原有明显的抑制作用。

Microbial reduction technology by S. oneidensis with ZⅥ was employed to treat U （ Ⅵ ） from wastewater. Anaerobic experiments were conducted to evaluate the influence of coexistent ions such as Cr6＋, Fe3＋, Cu2＋, Zn2＋, NO3- and SO42- on the reductive removal rate of U（ Ⅵ ）. The results demonstrated that coexistence of Cr6＋ and Fe3＋ showed a remarkable negative effect on U （ Ⅵ ） reduction, and the reduction of U （ Ⅵ ） was completely inhibited with the concentration of Cr6＋ more than 10.0 mg/L. Coexistence of Cu2＋ and Zn2＋ showed a remarkable negative effect on U（ Ⅵ ） reduction with the concentration 20.0 mg/L, and Zn2＋ has less influence on the process, while coexistence of Mn2＋ of 20.0 mg/L could slightly promote U（ Ⅵ ） reduction. SO4 2- has weak promotion, and the effect on the reduction of U（ Ⅵ ） is positive correlated with its concentration. When the concentration of NO3- was in the range of 0.5-5.0 mmol/L, it could cause seriously inhibition on the reduction of U（ Ⅵ ） at 12 h.