title: Biosorption of uranium on Bacillus sp. dwc-2: preliminary investigation on mechanism.
abstract: In this paper, the biosorption mechanisms of uranium on an aerobic Bacillus sp. dwc-2, isolated from a potential disposal site for (ultra-) low uraniferous radioactive waste in Southwest China, was explored by transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, FT-IR spectroscopy, proton induced X-ray emission (PIXE) and enhanced proton backscattering spectrometry (EPBS). The biosorption experiments for uranium were carried out at a low pH (pH 3.0), where the uranium solution speciation is dominated by highly mobile uranyl ions. The bioaccumulation was found to be the potential mechanism involved in uranium biosorption by Bacillus sp. dwc-2, and the bioaccumulated uranium was deposited in the cell interior as needle shaped particles at pH 3.0, as revealed by TEM analysis as well as EDX spectra. FTIR analysis further suggested that the absorbed uranium was bound to amino, phosphate and carboxyl groups of bacterial cells. Additionally, PIXE and EPBS results confirmed that ion-exchange also contributed to the adsorption process of uranium. All the results implied that the biosorption mechanism of uranium on Bacillus sp. is complicated and at least involves bioaccumulation, ion exchange and complexation process.
authors.affiliation: Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, PR China.
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Li
authors.affiliation: Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, PR China; Key Laboratory of Biological Resource and Ecological Environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, PR China.
authors.forename: Congcong
authors.initials: C
authors.lastname: Ding
authors.affiliation: Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, PR China. Electronic address: liaojiali@scu.edu.cn.
authors.forename: Jiali
authors.initials: J
authors.lastname: Liao
authors.affiliation: Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, PR China.
authors.forename: Tu
authors.initials: T
authors.lastname: Lan
authors.affiliation: Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, PR China.
authors.forename: Feize
authors.initials: F
authors.lastname: Li
authors.affiliation: Institute of Nuclear Physics and Chemistry, CAEP, Mianyang 621900, PR China.
authors.forename: Dong
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, PR China.
authors.forename: Jijun
authors.initials: J
authors.lastname: Yang
authors.affiliation: Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, PR China.
authors.forename: Yuanyou
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Institute of Nuclear Physics and Chemistry, CAEP, Mianyang 621900, PR China.
authors.forename: Shunzhong
authors.initials: S
authors.lastname: Luo
authors.affiliation: Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, PR China.
authors.forename: Jun
authors.initials: J
authors.lastname: Tang
authors.affiliation: Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, PR China. Electronic address: nliu720@scu.edu.cn.
authors.forename: Ning
authors.initials: N
authors.lastname: Liu
mesh_terms: D001407:Bacillus / Q000378:metabolism*; D001673:Biodegradation, Environmental; D014501:Uranium / Q000378:metabolism*
chemical_list: D014501:Uranium
keywords: Aerated zone soil; Bacillus sp. dwc-2; Biosorption mechanism; Uranium