▎ 摘　　要

NOVELTY - Modified graphene film useful for separating monovalent and polyvalent metal ion comprises slightly reduced graphene oxide containing carbon and oxygen in a mass ratio of 1.2-1.4 as film material, and two-dimensional nano-mass transfer channels of slight reduction of graphene sheets for intercepting monovalent metal ions and polyvalent metal ions. USE - The modified graphene film useful for separating monovalent and polyvalent metal ion. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing the modified graphene film, comprising (i) dispersing the slightly reduced graphene oxide in water to form a casting solution having 0.20-0.30 mg/ml concentration, (ii) filtering the casting solution obtained in the step (i) with a substrate film to form a wet modified graphene film on the substrate film, (iii) placing the wet modified graphene film together with the substrate film in normal temperature for drying, and film peeling off the dried modified graphene film to obtain modified graphene film.