一株分离自华南离子吸附型稀土矿的短小芽孢杆菌对稀土元素的吸附行为及机理研究  

Adsorption behavior and mechanism of REEs by Bacillus pumilus isolated from ion adsorption REE deposit in South China

作　　者：李旭锐 谭伟[1,2] 梁晓亮[1,2,3] 贺依琳[1,2,3] 王珩[1,2,3] 陈永林 何宏平 LI Xurui;TAN Wei;LIANG Xiaoliang;HE Yilin;WANG Heng;CHEN Yonglin;HE Hongping(CAS Key Laboratory of Mineralogy and Metallogeny/Guangdong Provincial Key Laboratory of Mineral Physics and Materials,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;CAS Center for Excellence in Deep Earth Science,Guangzhou 510640,Guangdong,China;University of Chinese Academy of Sciences,Beijing 100049,China;China Non-Ferrous Guilin Institute of Mineral Geology Co.Ltd.,Guilin 541000,Guangxi,China)

机构地区：[1]中国科学院广州地球化学研究所矿物学与成矿学重点实验室/广东省矿物物理与材料重点实验室,广东广州510640 [2]中国科学院深地科学卓越创新中心,广东广州510640 [3]中国科学院大学,北京100049 [4]中国有色桂林矿产地质研究院有限公司,广西桂林541000

出　　处：《地球化学》2024年第1期77-86,共10页Geochimica

基　　金：广东省基础与应用基础研究重大项目(2019B030302013);中国科学院地质与地球物理研究所重点部署项目(IGGCAS-201901);国家自然科学基金项目(42022012、41921003);广东省重点实验室运行项目(2020B1212060055)联合资助。

摘　　要：离子吸附型稀土矿是重要的表生矿床,提供了全球90%以上的重稀土。矿床中活跃的微生物能够通过吸附作用影响稀土元素的富集及分异,然而风化壳中的天然细菌对全配分稀土元素吸附行为及机理的相关研究仍然较为缺乏。本文选用离子吸附型稀土矿风化壳中分离出的短小芽孢杆菌,通过吸附实验研究在不同pH值、吸附时间和细菌浓度条件下,细菌对稀土元素的吸附行为。结果表明,短小芽孢杆菌对稀土元素的吸附容量最大可达41.9 mg/g,且重稀土元素在细菌细胞表面和水体之间的分配系数大于轻稀土元素。TEM图像显示,稀土元素在细菌表面形成沉淀;EDS分析显示,细胞表面大量Na、K、Ca等元素在与稀土元素发生离子交换后被脱除。细胞表面磷与稀土元素的分布一致性指示磷酸基团是稀土元素吸附的重要位点,重稀土元素通过与磷酸基团形成稳定的高配位络合物优先吸附在细菌表面。Zeta电位曲线表明,短小芽孢杆菌等电点为2.8,在高于等电点的pH值条件下,微生物对稀土的吸附存在静电吸引。因此,在表生环境中,微生物能够通过形成微沉淀、离子交换、表面络合和静电作用的多种机制吸附稀土元素,促进稀土元素的富集及分异。另外,短小芽孢杆菌有望作为潜在的生物吸附剂应用于稀土元素提取及回收。Ion adsorption rare earth element(REE)deposits are important supergene deposits,which provide more than 90%of heavy REE(HREE)in the world.Previous studies have shown that microorganisms in weathering crust can affect the enrichment and fractionation of REE through adsorption.However,studies on the adsorption behavior and mechanism of REE by natural bacteria in weathering crust are still rare.In this paper,Bacillus pumilus isolated from the weathering crust of ion adsorption REE deposits was selected to study the adsorption behavior of REE by bacteria under different initial pH values,adsorption times,and bacterial concentrations.The results showed that adsorption capacity of B.pumilus for REE was up to 41.9 mg/g,while the distribution coefficients of HREE between the surface of bacterial cells and water were greater than that of light REE(LREE).TEM images showed that REE precipitated on the surface of bacteria,and EDS analysis showed that a large number of Na,K,Ca and other elements on the cell surface were removed after ion exchange with REE.The colocalization of P and REE on cell surface indicates that phosphate group is an important site for REE adsorption.HREE preferentially adsorb on the bacterial surface by forming stable high coordination complex with the phosphate group.The Zeta potential curve showed that the isoelectric point of B.pumilus was 2.8,suggesting that adsorption mechanism of REE by microorganisms includes electrostatic attraction at pH higher than the isoelectric point.These results indicate that microorganisms can adsorb REE through various mechanisms including microprecipitation,ion exchange,surface complexation,and electrostatic interaction to promote the enrichment and fractionation of REE in the supergene environment.In addition,Bacillus pumilus is expected to be used as a potential bioadsorbent for the extraction and recovery of REE.

关 键 词：离子吸附型稀土矿 微生物吸附 稀土分异 吸附机制 

分 类 号：P595[天文地球—地球化学] Q93[天文地球—地质学]