The synthesis of core-shell magnetic dendritic fibrous nano-silica for the fast and selective capture of U(VI)

•A novel magnetic nanoparticle (Fe3O4@DFNS-NH2) with core-shell and fibrous structure was fabricated as the absorbent for U(VI).•The fibrous and open pores of Fe3O4@DFNS-NH2 facilitate the transfer and diffusion of U(VI) ions.•Fe3O4@DFNS-NH2 exhibited fast adsorption kinetics and good selectivity toward U(VI).•The interaction mechanism was proposed.