Surface functionalization graphene oxide by polydopamine for high affinity of radionuclides

The utilization of nuclear energy plays an important role in our energy system; however, the leaking of radionuclides has potential threat to human health. In this paper, two-dimensional polydopamine/ graphene oxide (PD/GO) composites were synthesized through a simple bio-inspired surface functionalization process by self-polymerization of dopamine monomers on GO surface. To evaluate the adsorption performance of PD/GO composites, the adsorbent was applied to remove uranium(VI) from aqueous solutions. Based on the Langmuir's equation, the maximum adsorption capacity was calculated to be 145.39 mg.g(-1) by PD/GO composites, which is higher than that of pure PD (34.21 mg.g(-1)) and GO (75.71 mg.g(-1)). The enhanced adsorption capacity was mainly ascribed to the synergistic effect of PD with multifunctional groups and GO with high surface area. The adsorption process fitted well with the Langmuir adsorption isotherm and a pseudo-second order kinetics. Moreover, adsorption and regeneration experiment proved the samples can support long-term use in nuclear waste management. This work provides a convenient and promising materials for the removal of U(VI) from polluted water. (C) 2015 Elsevier B.V. All rights reserved.