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...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.展开更多
基金supported by the China Ocean Mineral Resources Research Program (No. DY125-15-T-08)the National Natural Sciences Foundation of China (Nos. 21176026 21176242)
文摘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.
