▎ 摘　　要

NOVELTY - A sodium alginate/cattail/graphene oxide composite aerogel comprises sodium alginate, cattail and graphene oxide. The internal structure of composite aerogel is honeycomb layer porous structure sandwiched between parallel layer structures. USE - Sodium alginate/cattail/graphene oxide composite aerogel for oil-water separation or adsorption removal of water-soluble dye such as gentian violet, methylene blue or rhodamine B (all claimed). ADVANTAGE - The environmentally-friendly and economical sodium alginate/cattail/graphene oxide composite aerogel adopts simple and efficient method and ensures excellent underwater super-oleophobicity. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of sodium alginate/cattail/graphene oxide composite aerogel, which involves (1) preparing sodium alginate/cattail/graphene oxide mixed solution by (A) preparing a graphene oxide dispersion, (B) preparing cattail fiber by adding sodium chlorite to deionized water, stirring to obtain sodium chlorite solution, adjusting pH, adding cattail flower spikes, stirring, washing with deionized water to adjust pH to 6, washing repeatedly with absolute ethanol for three times and drying to obtain dried cattail fiber, (C) adding sodium alginate powder and cattail fiber to graphene oxide dispersion, stirring, ultrasonically processing to obtain homogeneous mixed solution of sodium alginate/cattail/graphene oxide, (2) preparing uncrosslinked sodium alginate/cattail/graphene oxide composite aerogel by pouring sodium alginate/cattail/graphene oxide mixed solution to bottom of wedge of silicone mold, covering outer portion of mold with thermal insulation tape to prevent temperature from getting transmitted to each other, contacting bottom of the silicone mold with a top of a copper rod that is continuously cooled by liquid nitrogen for two-way freeze casting, freeze-drying (I), when the solution is frozen into ice, and obtaining uncrosslinked sodium alginate/cattail/graphene oxide composite aerogel, (3) immersing uncrosslinked sodium alginate/cattail/graphene oxide composite aerogel in ethanol/water mixed solution of calcium chloride, repeatedly cleaning the aerogel with absolute ethanol and freeze drying (II).