title: Enhanced U(VI) bioreduction by alginate-immobilized uranium-reducing bacteria in the presence of carbon nanotubes and anthraquinone-2,6-disulfonate.
abstract: Uranium-reducing bacteria were immobilized with sodium alginate, anthraquinone-2,6-disulfonate (AQDS), and carbon nanotubes (CNTs). The effects of different AQDS-CNTs contents, U(IV) concentrations, and metal ions on U(IV) reduction by immobilized beads were examined. Over 97.5% U(VI) (20 mg/L) was removed in 8 hr when the beads were added to 0.7% AQDS-CNTs, which was higher than that without AQDS-CNTs. This result may be attributed to the enhanced electron transfer by AQDS and CNTs. The reduction of U(VI) occurred at initial U(VI) concentrations of 10 to 100 mg/L and increased with increasing AQDS-CNT content from 0.1% to 1%. The presence of Fe(III), Cu(II) and Mn(II) slightly increased U(VI) reduction, whereas Cr(VI), Ni(II), Pb(II), and Zn(II) significantly inhibited U(VI) reduction. After eight successive incubation-washing cycles or 8 hr of retention time (HRT) for 48 hr of continuous operation, the removal efficiency of uranium was above 90% and 92%, respectively. The results indicate that the AQDS-CNT/AL/cell beads are suitable for the treatment of uranium-containing wastewaters.
authors.affiliation: Civil and Environmental Engineering School, University of Science and Technology Beijing, Beijing 100083, China; National Key State Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China. Electronic address: wangweida888@163.com.
authors.forename: Weida
authors.initials: W
authors.lastname: Wang
authors.affiliation: Civil and Environmental Engineering School, University of Science and Technology Beijing, Beijing 100083, China. Electronic address: ylfeng126@126.com.
authors.forename: Yali
authors.initials: Y
authors.lastname: Feng
authors.affiliation: National University of Singapore, Department of Civil and Environmental Engineering, Centre for Water Research, Singapore 117576, Singapore.
authors.forename: Xinhua
authors.initials: X
authors.lastname: Tang
authors.affiliation: National Key State Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China. Electronic address: hrli@home.ipe.ac.cn.
authors.forename: Haoran
authors.initials: H
authors.lastname: Li
authors.affiliation: National Key State Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Zhuwei
authors.initials: Z
authors.lastname: Du
authors.affiliation: Civil and Environmental Engineering School, University of Science and Technology Beijing, Beijing 100083, China.
authors.forename: Aifei
authors.initials: A
authors.lastname: Yi
authors.affiliation: Civil and Environmental Engineering School, University of Science and Technology Beijing, Beijing 100083, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000880:Anthraquinones / Q000737:chemistry*; D001419:Bacteria / Q000145:classification / Q000378:metabolism*; D018914:Cells, Immobilized; D055664:Electrochemical Techniques; D037742:Nanotubes, Carbon / Q000737:chemistry*; D014501:Uranium / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D000464:Alginates; D000880:Anthraquinones; D037742:Nanotubes, Carbon; C408124:anthraquinone-2,6-disulfonate; D014501:Uranium
keywords: Anthraquinone-2,6-disulfonate (AQDS); Carbon nanotubes (CNTs); Immobilization; Redox mediator; Uranium