Graphene oxide based dopamine mussel-like cross-linked polyethylene imine nanocomposite coating with enhanced hexavalent uranium adsorption

Polydopamine (pDA) self-polymerized from mussel-substance dopamine (DA) induced the grafting of polyethylene imine (PEI) between graphene oxide (GO) interlayers to form the GO-pDA-PEI adsorbent for capturing U(VI). The as-prepared GO-pDA-PEI has a hexavalent uranium (U(VI)) adsorption capacity of 530.6 mg g⁻¹, which is 177% higher than that of pristine GO. Both thermodynamic and kinetic studies indicate a spontaneous and exothermic chemisorption process. The adsorbent demonstrates high adsorption capability and stability even after 5cycles of adsorption–desorption processes. The enhanced U(VI) adsorption capability was due to the unique characteristics of the nanoadsorbent, i.e., the ability to provide enough movement space and highly active sites for the adsorption of U(VI).