Sorption of Pb(II) and Cu(II) onto multi-amine grafted mesoporous silica embedded with nano-magnetite: Effects of steric factors

► Synthesis of amine grafted MSU-F-S/Fe3O4 for easy separation after sorption. ► Non-linearity between sorption properties and the number of amine groups. ► Pore blockage occurred by excessively loaded multi-amine functional groups. ► Conformational changes of amine groups depending on pH caused the steric hindrance.