▎ 摘　　要

NOVELTY - Sodium lignosulfonate/graphene oxide composite material comprises graphene oxide solution and sodium lignosulfonate solution. USE - The composite material is useful for adsorbing chromium ions in wastewater treatment (claimed). ADVANTAGE - The composite material: has large specific surface area and more active adsorption sites, strong ability to adsorb metal ions (preferably chromium(VI) ions), 88% efficiency after 5 cycles of recovery and reuse of materials through desorption-adsorption experiments, high reuse efficiency after desorption, and high wastewater treatment effect; and does not generate secondary pollution. The method is simple and low cost, has mild experimental conditions, and consumes less energy. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing the composite material, comprising (i) preparing graphene oxide solution, (ii) adding sodium lignosulfonate solution into the graphene oxide solution, and treating ultrasonically to obtain mixed solution, and (iii) pouring the mixed solution into PTFE-lined reaction kettle, reacting, cooling to room temperature, and washing to obtain final product.