Selective adsorption of uranium from aqueous solution by mesoporous polymer-carbon composites containing phosphate groups

Abstract

In the present study, ordered mesoporous polymer-carbon composites (CMK-3) containing phosphate groups (xPCMK-3) were constructed by in-situ polymerization of vinyl phosphoric acid. xPCMK-3 were well encapsulated by phosphate groups and showed excellent performance in removing U(VI). It is worth noting that 0.2PCMK-3 achieved the maximum U(VI)-adsorption capacity (405.5 mg g−1) within 35 min. Besides, 0.2PCMK-3 obeyed the pseudo-second-order kinetic model and Langmuir adsorption isotherm model. The thermodynamic parameters indicated that adsorption of uranium was a spontaneous, endothermic and chemical process. Due to the excellent chemical stability, the U(VI)-adsorption capability of 0.2PCMK-3 nanospheres could still maintain at 84.5% of the original level after 5 adsorption-desorption cycles. More importantly, phosphate groups in 0.2PCMK-3 were found to play an important part in the U(VI) removal and selection in competitive cation solutions. The results of this study further confirmed that 0.2PCMK-3 were a promising material for treatment of uranium pollutants in the water environment.