▎ 摘　　要

NOVELTY - A composite material comprises biological carbon and graphene, where graphene is coated on carbon surface. USE - Composite material used for adsorbing water organic/inorganic pollutants, particularly phenanthrene and mercury (II) (claimed). ADVANTAGE - The composite material has simple and stable process, is environment-friendly, and has no secondary pollution. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) preparation of composite material comprising taking 10 mg, 50 mg, 100 mg graphene powder, adding to 100 mL deionized water, and mixing to obtain 100, 500, 1000 mg/L graphene suspension; taking wheat straw, airing, crushing, ultrasonically washing for 2 hours, adding 5 g wheat straw to 50 mL graphene suspension, magnetically stirring for 1 hour, drying at 80 degrees C for 3 hours, and calcining at 600 degrees C under nitrogen gas anoxytropic splitting; and adding 1 M hydrochloric acid, repeatedly washing with distilled water until neutral, and drying 80 degrees C; and (2) detection of phenanthrene pollutants comprising using HPLC with mobile phase of acetonitrile and water at volume ratio of 7:3, where flow rate of 1.0 mL/minute, injection volume of 80 mu L, oven temperature of 30 degrees C, and detection wavelength of 280 nm.