微生物矿化去除地浸采铀地下水中污染物的试验研究  

Experimental study on microbial mineralization for removing contaminants from groundwater in mining areas of in-situ uranium leaching

作　　者：贺桂成 朱小裕 李咏梅 HE Guicheng;ZHU Xiaoyu;LI Yongmei(School of Resource Environment and Safety Engineering,University of South China,Hengyang 421001,China)

机构地区：[1]南华大学资源环境与安全工程学院,衡阳421001

出　　处：《核技术》2024年第6期35-44,共10页Nuclear Techniques

基　　金：国家重点研发计划项目(No.2021YFC2902104);国家自然科学基金(No.51974163,No.52274127);湖南省自然科学基金(No.2023JJ40522);湖南省教育厅优秀青年项目(No.22B0430)资助。

摘　　要：微生物诱导碳酸钙沉淀(Microbial-induced Calcium Carbonate Precipitation,MICP)技术能较好地矿化去除地下水中的污染物。本文选用巴氏芽孢杆菌,分析其耐酸性以及对铀的耐受性,探究初始U(Ⅵ)浓度、Ca^(2+)浓度、pH值、菌液浓度和矿化作用时间等因素对MICP去除污染物的影响,揭示MICP矿化去污的机理。研究结果表明:巴氏芽孢杆菌在pH为4时具有较好的脲酶活性,可以适应含U(Ⅵ)浓度为100 mg·L^(-1)的地下水;当初始pH为4、铀浓度为50 mg·L^(-1)、Ca^(2+)浓度为8000 mg·L^(-1)、MICP矿化作用时间为48 h时,地下水中的U(Ⅵ)的去除率为61%、钙去除率为54%,但当初始pH升高到7时,U(Ⅵ)的去除率增加到91%。Ca^(2+)浓度的升高有助于MICP矿化去除地下水中的U(Ⅵ),但Ca2+浓度过高时其自身的被去除率相对较低。MICP矿化产物的成分为含铀的碳酸钙,其中,铀主要以共沉淀的方式被固定。[Background]The remediation technology for U(VI),Ca^(2+)and other pollutants in the groundwater of the mining area of in-situ leaching of uranium has become a key technical bottleneck restricting the decommission of uranium mine,and the microbial-induced calcium carbonate precipitation(MICP)technology can well mineralize and remove heavy metals in the groundwater.[Purpose]This study aims to remove the pollutants in groundwater of uranium mining areas with MICP.[Methods]First of all,bacillus pasteurianus was selected,and its acid resistance and tolerance to uranium were analyzed.Then,the effects of initial U(VI)concentration,initial Ca^(2+)concentration,initial pH value,concentration of bacterial solution,and the time of mineralization on the removal of pollutants by MICP were explored.In addition,scanning electron microscopy(SEM)and X-ray diffraction spectroscopy(XRD)were employed to characterize the composition and microstructure of the mineralization products of MICP,in order to reveal the mechanism of mineralization and decontamination.Finally,water with low uranium concentration was treated by bacillus pasteurianus to verify the application of MICP.[Results]The results show that Bartonella pasteurii has good urease activity at pH value of 4 and can adapt to the groundwater containing U(VI)concentration of 100 mg∙L^(−1).When the initial pH value is 4,the initial uranium concentration is 50 mg∙L^(−1),the Ca^(2+)concentration is 8000 mg∙L^(−1),and the time of mineralization by MICP is 48 h,the removal rates of U(VI)and Ca^(2+)in the groundwater are 61%and 54%,respectively.The removal rate of U(VI)further increases to 91%when the initial pH value is increased to 7.Meanwhile,the increase of Ca^(−1)concentration promotes the removal of U(VI)in groundwater by MICP,however,the removal rate of Ca^(−1)is relatively low if the concentration of Ca^(−1)is too high.[Conclusions]The composition of MICP mineralization products is mainly uranium-containing calcium carbonate,in which the uranium is immobilize

关 键 词：微生物矿化 地浸采铀 地下水 铀 污染物 

分 类 号：TL75[核科学技术—辐射防护及环境保护]