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 ). GO-pDA-PEI with excellent stability provided enough movement space and active sites for highly preferential adsorption of U( vi ).