丝状真菌黑曲霉对放射性核素U(Ⅵ)的吸附、富集和转化  

Adsorption, bioconcentration and transformation of radioactive U(Ⅵ) on filamentous fungi Aspergillus Niger

作　　者：梁君[1] 刘磊[2] 汤克来 宋文成[2] Jun Liang;Lei Liu;Kelai Tang;Wencheng Song(Jianghuai College,Anhui University,Hefei 230039,China;Anhui Province Key Laboratory of Medical Physics and Technology,Center of Medical Physics and Technology,Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,China;Agricultural Technology Station,Stone Town,Lufiang County,Hefei City,Anhui Province,Hefei 231524,China)

机构地区：[1]安徽大学江淮学院,合肥230039 [2]中国科学院合肥物质科学研究院医学物理与技术中心医学物理与技术安徽省重点实验室,合肥230031 [3]安徽省合肥市庐江县石头镇农技站,合肥231524

出　　处：《中国科学：化学》2019年第1期113-122,共10页SCIENTIA SINICA Chimica

基　　金：国家自然科学基金(编号:21607156);中国博士后科学基金(编号:2015M581047)资助项目

摘　　要：本文采用批试验和X射线吸收精细结构谱学(XAFS)技术系统研究了黑曲霉菌丝体对放射性核素U(Ⅵ)的吸附、富集和转化.宏观研究表明,时间、菌丝体浓度、pH和温度显著影响菌丝体吸附U(Ⅵ),吸附动力学符合准二级动力学模型;吸附等温线符合Langmuir模型,在pH 6.0, T=298 K条件下,菌丝体吸附U(Ⅵ)的最大吸附量是83.73 mg/g,比其他生物吸附剂有较高的吸附U(Ⅵ)能力.黑曲霉富集U(Ⅵ)后,胞内外形态结构明显改变,并且胞内H_2O_2、丙二醛(MDA)和巯基化合物浓度显著增加.使用X射线吸收近边缘结构(XANES)分析证实黑曲霉胞内U(Ⅵ)减少,被还原为U(Ⅳ);扩展X射线吸收精细结构(EXAFS)数据表明, U(Ⅳ)产物是由单核U(Ⅳ)原子紧密包围的轻元素壳组成的形态,这种原子排列可能由U(Ⅳ)和C/N/O–或含P/S的配体(如碳酸根或磷酸根)之间的内球键产生.研究结果表明,丝状真菌黑曲霉有望应用于放射性核素U(Ⅵ)污染的修复治理.The adsorption, bioconcentration and transformation of radionuclides U（Ⅵ） by Aspergillus niger（A. niger）were studied. Batch experiments showed that the adsorption of U（Ⅵ） by A. niger was influenced by time, adsorbent concentration, pH value and temperature. The adsorption reached equilibrium within 48 h, and the adsorption kinetics complied with the pseudo-second-order kinetics model. The Langmuir model was more consistent with the adsorption isotherm than the Freundlich model, and the maximum adsorption of U（Ⅵ） by mycelia was 83.73 mg/g at pH 6.0 and T=298 K, which was higher than other biosorbents. After bioconcentration of U（Ⅵ） by A. niger, the intracellular and extracellular morphological structures changed significantly, and the concentrations of intracellular H2O2,malonaldehyde（MDA） and thiol compounds in mycelia increased obviously. X-ray absorption near-edge structure（XANES） analysis confirmed that the intracellular U（Ⅵ） of A. niger was reduced to U（Ⅳ）, and EXAFS data indicated that the U（Ⅳ） product was a phase composed of mononuclear U（Ⅳ） atoms closely surrounded by light element shells.The results showed that the filamentous fungus A. niger can be used as a potential biological material for radionuclide removal, which has important scientific significance and potential application value.

关 键 词：黑曲霉 吸附 富集 U(VI) X射线吸收精细结构谱学(XAFS) 

分 类 号：O647.3[理学—物理化学]