Li Xiaolong, Ding Congcong, Liao Jiali, Du Liang, Sun Qun, Yang Jijun, Yang Yuanyou, Zhang Dong, Tang Jun, Liu Ning
Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, China.
Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, China; Key Laboratory of Biological Resource and Ecological Environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China.
J Environ Sci (China). 2016 Mar;41:162-171. doi: 10.1016/j.jes.2015.06.007. Epub 2015 Aug 12.
The biosorption mechanisms of uranium on an aerobic bacterial strain Streptomyces sporoverrucosus dwc-3, isolated from a potential disposal site for (ultra-)low uraniferous radioactive waste in Southwest China, were evaluated by using transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), proton induced X-ray emission (PIXE) and enhanced proton backscattering spectrometry (EPBS). Approximately 60% of total uranium at an initial concentration of 10mg/L uranium nitrate solution could be absorbed on 100mg S. sporoverrucosus dwc-3 with an adsorption capacity of more than 3.0mg/g (wet weight) after 12hr at room temperature at pH3.0. The dynamic biosorption process of S. sporoverrucosus dwc-3 for uranyl ions was well described by a pseudo second-order model. S. sporoverrucosus dwc-3 could accumulate uranium on cell walls and within the cell, as revealed by SEM and TEM analysis as well as EDX spectra. XPS and FT-IR analysis further suggested that the absorbed uranium was bound to amino, phosphate and carboxyl groups of the cells. Additionally, PIXE and EPBS results confirmed that ion exchange also contributed to the adsorption process of uranium.
从中国西南部一个潜在的（超）低铀放射性废物处置场分离出的需氧细菌菌株多疣孢链霉菌dwc - 3对铀的生物吸附机制，通过透射电子显微镜（TEM）、能量色散X射线（EDX）分析、傅里叶变换红外光谱（FT - IR）、X射线光电子能谱（XPS）、质子诱导X射线发射（PIXE）和增强质子背散射光谱（EPBS）进行了评估。在初始浓度为10mg/L硝酸铀溶液中，约60%的总铀在室温pH3.0条件下12小时后可被100mg多疣孢链霉菌dwc - 3吸附，吸附容量超过3.0mg/g（湿重）。多疣孢链霉菌dwc - 3对铀酰离子的动态生物吸附过程可用准二级模型很好地描述。扫描电子显微镜（SEM）、透射电子显微镜（TEM）分析以及EDX光谱显示，多疣孢链霉菌dwc - 3可在细胞壁和细胞内积累铀。XPS和FT - IR分析进一步表明，吸附的铀与细胞的氨基、磷酸基和羧基结合。此外，PIXE和EPBS结果证实离子交换也有助于铀的吸附过程。
