芽孢杆菌Bacillus sp.dwc-2对模拟地下水中U(Ⅵ)的还原行为研究  

Reduction Behavior of U(Ⅵ) by Bacillus sp.dwc-2 in Simulated Groundwater under Anaerobic Condition

作　　者：王静[1] 刘军[1,2] 赵长菘[1] 涂鸿 贺含毅 杨吉军 廖家莉[1] 杨远友[1] 刘宁[1] WANG Jing;LIU Jun;ZHAO Changsong;TU Hong;HE Hanyi;YANG Jijun;LIAO Jiali;YANG Yuanyou;LIU Ning(Key Laboratory of Radiation Physics and Technology,Ministry of Education,Institute of Nuclear Science and Technology,Sichuan University,Chengdu 610064,China;College of Nuclear Technology and Automation Engineering,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]四川大学原子核科学技术研究所,辐射物理及技术教育部重点实验室,四川成都610064 [2]成都理工大学核技术与自动化工程学院,四川成都610059

出　　处：《原子能科学技术》2020年第1期6-13,共8页Atomic Energy Science and Technology

基　　金：国家自然科学基金资助项目(91126013,21876123);国家基础科学人才培养基金特殊学科点资助项目(J1210004)

摘　　要：在厌氧条件下研究了西南地区一种典型土壤微生物芽孢杆菌Bacillus sp.dwc-2对模拟地下水中U(Ⅵ)的还原行为,重点考察了时间、无机阴离子、腐殖酸(HA)及富里酸(FA)对还原的影响,并利用TEM、EDS、SAED和XPS对还原后的样品进行了表征。结果表明:在pH=7.0、cNaHCO3=5 mmol/L和T=303 K条件下,Bacillus sp.dwc-2对U(Ⅵ)的还原率随时间的增加而增加,24 h内最大还原率为12.2%,此后则随时间的增加逐渐降低;HA和FA对U(Ⅵ)的微生物还原行为有一定影响,其中HA和FA浓度为25 mg/L时,U(Ⅵ)的还原在24 h最明显,其还原率分别为14.2%和16.2%,但随着HA和FA浓度的继续增加,因在U(Ⅵ)离子与HA、FA形成的配合物表面形成致密的腐殖层,抑制了电子的转移,阻止了U(Ⅵ)的还原。此外,研究表明HCO3-也会抑制U(Ⅵ)的还原。TEM-SAED和XPS分析证实了还原过程中U(Ⅳ)的存在。上述结果可为真实环境中微生物还原U(Ⅵ)提供基础数据和参考。The reduction behavior and the effect of various experimental conditions on U(Ⅵ) reduction by Bacillus sp.dwc-2 were investigated under anaerobic conditions at cNaHCO3=5 mmol/L, T=303 K and pH=7.0 in simulated groundwater. TEM, EDS, SAED and XPS were carried out for sample characterization. The results show that the reduction rate increases with the contact time. The maximum U(Ⅵ) reduction rate at 24 h is 12.2%, and the reduction rates of 14.2% and 16.2% are achieved in the presence of HA and FA. The reduction rate of U(Ⅵ) increases with HA and FA concentration from 0 mg/L to 25 mg/L, then decreases due to the formation of humic coatings on the surfaces of complexes of HA and FA with U(Ⅵ) at the relatively high humic concentrations. In addition, HCO3- also inhibits the reduction of U(Ⅵ). Analysis of TEM-SAED and XPS confirms the existence of U(Ⅳ) during the reduction process. The above results provide basic data and reference for the reduction of U(Ⅵ) under real environment.

关 键 词：芽孢杆菌 HA FA U(Ⅵ) 还原 

分 类 号：TL93[核科学技术—辐射防护及环境保护]