Immobilization of carboxyl-modified multiwalled carbon nanotubes in chitosan-based composite membranes for U(VI) sorption

The carboxyl-modified multiwalled carbon nanotubes were immobilized in chitosan-based composite membranes (CS-CNTs) which were used as efficient sorbents for U(VI) sorption. The incorporation of CNTs in the CS-CNTs membranes improves their mechanical strength as well as U(VI) sorption performance. XPS analysis indicates that both amine and carboxyl groups are responsible for the complexation of U(VI). The sorption kinetics followed the pseudo-second order equation, whereas the sorption isotherms fitted well with Langmuir model ( q m  = 126.7 mg g −1 at 298 K). Moreover, the U(VI)-loaded CS-CNT8 can be effectively desorbed by 0.2 M acidified EDTA and reused.