Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2015, Vol. 26 ›› Issue (6): 060301 doi: 10.13538/j.1001-8042/nst.26.060301


Biosorption behavior and mechanism of thorium on Bacillus sp. dwc-2 isolated from soil

LAN Tu,1 DING Cong-Cong,1, 2 LIAO Jia-Li,1 LI Xiao-Long,1 LI Xing-Liang,3 ZHANG Jie,2 ZHANG Dong,3 YANG Ji-Jun,1 LUO Shun-Zhong,3 AN Zhu,1 WU Qi-Qi,1 YANG Yuan-You,1 FENG Su,2 TANG Jun,1 LIU Ning1   

  1. 1Key Laboratory of Radiation Physics and Technology (Sichuan University), Ministry of Education; Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, China
    2Key Laboratory of Biological Resource and Ecological Environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
    3Institute of Nuclear Physics and Chemistry, CAEP, Mianyang, 621900, China
  • Contact: LIAO Jia-Li;LIU Ning;
  • Supported by:

    Supported by National Natural Science Foundation of China (Nos. 21071102 and 91126013), Joint Funds of China National Natural Science Foundation and China Academy of Engineering Physics (No. U1330125) and the National Fund of China for Fostering Talents in Basic Science (No. J1210004)

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LAN Tu, DING Cong-Cong, LIAO Jia-Li, LI Xiao-Long, LI Xing-Liang, ZHANG Jie, ZHANG Dong, YANG Ji-Jun, LUO Shun-Zhong, AN Zhu, WU Qi-Qi, YANG Yuan-You, FENG Su, TANG Jun, LIU Ning. Biosorption behavior and mechanism of thorium on Bacillus sp. dwc-2 isolated from soil.Nuclear Science and Techniques, 2015, 26(6): 060301     doi: 10.13538/j.1001-8042/nst.26.060301


To develop a microbe-based bioremediation strategy for cleaning up thorium-contaminated sites, we have investigated the biosorption behavior and mechanism of thorium on Bacillus sp. dwc-2, one of the dominant species of bacterial groups isolated from soils in Southwest China. Thorium biosorption depended on the pH of environment, and its rapid biosorption reached a maximum of up to 10:75 mg Th per gram of the bacteria (wet wt.) at pH 3.0. The biosorption agreed bettter with Langmuir isotherm model than Freundlich model, indicating that thorium biosorption was a monolayer adsorption. The thermodynamic parameters, negative change in Gibbs free energy and positive value in enthalpy and entropy, suggested that the biosorption was spontaneous, more favorable at higher temperature and endothermic process with an increase of entropy. Scanning electron microscopy (SEM) indicated that thorium initially binded with the cell surface, while transmission electron microscopy (TEM) revealed that Th deposited in the cytoplasm and served as cores for growth of element precipitation (e.g., phosphate minerals) or by self-precipitation of hydroxides, which is probably controlled by ion-exchange, as evidenced by particle induced X-ray emission (PIXE) and enhanced proton backscattering spectrometry (EPBS). Fourier Transform Infrared (FTIR) further indicated that thorium biosorption involved carboxyl and phosphate groups and protein in complexation or electrostatic interaction. Overall results indicated that a combined electrostatic interaction-complexation-ion exchange mechanism could be involved in thorium biosorption by Bacillus sp. dwc-2.

Key words: Thorium, Bacillus sp., Biosorption, Mechanism, Transmission electron microscopy (TEM), Particle induced X-ray emission (PIXE), Enhanced proton backscattering spectrometry (EPBS)