▎ 摘　　要

NOVELTY - Preparing graphene-based double-network polyethylenimine-graphene oxide/sodium alginate (PEI-GO)/SA composite material comprises (a) adding crosslinking agent glutaraldehyde (GA) to the PEI-GO dispersion to obtain GA crosslinked PEI-GO three-dimensional gel, immersing in water, removing unreacted GA, and freeze-drying to obtain GA cross-linked PEI-GO aerogel, (b) immersing the GA crosslinked PEI-GO aerogel in SA solution and filtering to obtain a PEI-GO/SA composite gel, and (c) immersing the PEI-GO/SA composite gel in a calcium (II) solution and filtering to obtain calcium(II)-crosslinked double-network PEI-GO/SA gel which is freeze-dried to obtain double crosslinked double network PEI-GO/SA aerogel composite material. USE - The method is useful for preparing PEI-GO/SA composite material which is useful for dye adsorption. ADVANTAGE - The PEI-GO/SA composite material: removes methylene blue in wastewater, that reaches more than 90%, and realizes easy separation from water after adsorption; is non-toxic and does not cause secondary pollution.