▎ 摘　　要

NOVELTY - Preparing three dimensional graphene composite material involves oxidizing graphite, washing and ultrasonic filtering to obtain graphene oxide followed by second oxidation of graphene oxide, washing and ultrasonic filtering to obtain graphene oxide sheets. The graphene oxide sheets are mixed with polyethyleneimine in mass ratio of 2-10:1 at room temperature. The resulting graphene sheets are dispersed in water, and again added to solution of polyethyleneimine. The resultant is freeze dried to obtain graphene composite material. USE - Method for preparing three dimensional graphene composite material for adsorbing heavy metal ions (claimed). ADVANTAGE - The method enables to prepare three dimensional graphene composite material with strong absorbing ability, large load capacity and can be recycled for repeated use.