Direct surface modification of nanodiamonds with ionic copolymers for fast adsorptive removal of copper ions with high efficiency

•Direct surface modification of ND with ionic copolymers.•The Ce(IV)/HNO3 redox polymerization is a simple and useful method for surface modification.•ND-poly(AA-co-MPC) show greater enhancement adsorption capacity towards copper ions.•This method could also be expanded for fabrication of many other polymeric nanocomposites.