▎ 摘　　要

NOVELTY - Preparing multi-level structure graphene/polyimide composite sponge comprises (1) uniformly dispersing graphene in deionized water, adding polyethylene glycol to stir for 2-3 hours, and dialyzing with dialysis bag to remove dispersion graphene, (2) adding silicon dioxide to N,N-dimethylformamide, adding silane coupling agent, adding 4,4-diaminodiphenyl ether and pyromellitic anhydride under ice bath conditions and nitrogen atmosphere, stirring at room temperature, and dissolving obtained solution in deionized water, and (3) adding graphene dispersion in polyamic acid solution A, stirring at normal temperature makes the polyamic acid fully grafted on the graphene sheet, or adding the graphene dispersion liquid is added in the polyamic acid solution B or C that step (2) obtains, fully grafting the polyamic acid on the graphene sheet by stirring at room temperature, and thermally reducing after freeze-drying to obtain multi-level structure graphene/polyimide composite sponge. USE - The composite sponge is useful in adsorption of pollutant, oil-containing waste water, petroleum organic matter caused by sudden crude oil leakage and exploitation area source pollution, organic solvent and dyes. ADVANTAGE - The construction of the multi-level structure can greatly increase the specific surface area of the composite sponge, the holes and material gaps with different apertures in it can absorb various pollutants with different molecular sizes at the same time, the adsorption efficiency of the sponge is improved, and the oil pollution processing flow is simplified. The preparation cost of composite sponge is low, and it is easy to be produced in large scale. DETAILED DESCRIPTION - Preparing multi-level structure graphene/polyimide composite sponge comprises (1) uniformly dispersing graphene in deionized water, adding polyethylene glycol to stir for 2-3 hours, and dialyzing with dialysis bag to remove dispersion graphene, (2) adding silicon dioxide to N,N-dimethylformamide, adding silane coupling agent, adding 4,4-diaminodiphenyl ether and pyromellitic anhydride under ice bath conditions and nitrogen atmosphere, stirring at room temperature for 2-4 hours, adding triethylamine, uniformly stirring, dissolving the resulting solution in deionized in water, and obtaining the polyamic acid solution A containing silicon dioxide, adding 4,4-diaminodiphenyl ether and pyromellitic anhydride to N,N-dimethylformamide under ice bath conditions and nitrogen atmosphere, stirring at room temperature for 2-4 hours and adding triethylamine, dissolving the obtained solution in deionized water after uniformly stirring, adding paraffin wax and emulsifier, uniformly stirring the mixture with emulsifying shearing mixer to obtain polyamic acid solution B containing paraffin wax and emulsifier, or adding 4,4-diaminodiphenyl ether and pyromellitic anhydride to N,N-dimethylformamide under ice bath conditions and nitrogen atmosphere, adding polyetheramine or polyurethane, stirring and reacting at room temperature for 2-4 hours, adding triethylamine, uniformly stirring, and dissolving the obtained solution in deionized water to obtain polyetheramine or polyurethane-containing polyamic acid solution C, and (3) adding the graphene dispersion in the polyamic acid solution A obtained in the step (2), stirring at normal temperature makes the polyamic acid fully grafted on the graphene sheet, removing silicon dioxide by soaking in alkaline solution to obtain multi-level structure graphene/polyimide composite sponge after freeze-drying, thermal reduction is performed, or adding the graphene dispersion liquid is added in the polyamic acid solution B or C that step (2) obtains, fully grafting the polyamic acid on the graphene sheet by stirring at room temperature, and thermally reducing after freeze-drying to obtain multi-level structure graphene/polyimide composite sponge.