Subjects: Nuclear Science and Technology >> Nuclear Materials and Techniques submitted time 2023-06-18 Cooperative journals: 《Nuclear Science and Techniques》
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
Abstract： 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.
Subjects: Nuclear Science and Technology >> Nuclear Materials and Techniques submitted time 2023-06-18 Cooperative journals: 《Nuclear Science and Techniques》
LIU Xiao-Qing
YANG Yuan-You
LIAO Jia-Li
OU Wei
KONG Fang
LAN Jing-Bo
LUO Shun-Zhong
LIU Guo-Ping
HE Jia-Heng
YANG Ji-Jun
TANG Jun
LIU Ning
Abstract： Uranium removal efficacy of fullerence multi-macrocyclic polyamine derivatives (C60-MMP), a novel chelating agent, was evaluated in mice. C60-MMP was administrated intravenously into mice at 30 min after the uranium contamination. The molar ratio of chelating ligand/uranium was about 1:1. The results indicate that C60-MMP can effectively prevent accumulation of uranium in liver at 8 h after C60-MMP injection. At 48 h after the last injection, uranium deposition in liver of C60-MMP treated mice is approximately 65% less than that of the control group. C60-MMP reacted positively in promoting the removal of uranium from kidney, and the urinary uranium excretion increased significantly, compared with the control and DTPA-treated mice. However, repeated administration of C60-MMP, and combined injection of DTPA and C60-MMP, did not show desirable effects on uranium removal from mice. It implies that more investigations are needed for the treatment protocols and clinical applications of C60-MMP.
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