▎ 摘　　要

NOVELTY - Method for preparing graphene involves (a) dispersing expanded graphite in fermentation medium to obtain a graphite dispersion, adding fungal immobilized material to the fermentation medium to obtain a fermentation liquid and sterilizing the graphite dispersion and the fermentation liquid, (b) activating fungus, inoculating the activated fungus into fermentation medium and culturing in a constant temperature shaker to obtain a spore suspension, (c) adding the spore suspension to the fermentation liquid and culturing until the surface of the immobilized material is covered with mycelium to obtain fermentation liquid of the immobilized fungus, (d) adding the graphite dispersion to the fermentation liquid of the immobilized fungus, performing fermentation culture and then performing membrane filtration to obtain bio-oxidized graphite and (e) subjecting the bio-graphite oxide to supercritical carbon dioxide stripping and impurity removal to obtain the bio-graphene oxide. USE - The method is useful for preparing graphene. ADVANTAGE - The method is environmentally-friendly, produces large quantities of graphene flakes having excellent properties and low oxidation degree and reduces defects of graphene oxide caused by the use of strong acid in the chemical oxidation method, since it utilizes organic acids and other organic small molecules to insert between graphite layers. DETAILED DESCRIPTION - Method for preparing graphene involves (a) dispersing expanded graphite in fermentation medium to obtain a graphite dispersion, adding fungal immobilized material to the fermentation medium to obtain a fermentation liquid and sterilizing the graphite dispersion and the fermentation liquid respectively, (b) activating fungus, inoculating the activated fungus into fermentation medium and culturing in a constant temperature shaker for 24-36 hours at 25-55℃ and 150-220 revolutions per minute (rpm) to obtain a spore suspension, (c) adding the spore suspension to the fermentation liquid and culturing for 4-7 days at 25-55℃ and 150-220 rpm until the surface of the immobilized material is covered with mycelium to obtain fermentation liquid of the immobilized fungus, (d) adding the graphite dispersion to the fermentation liquid of the immobilized fungus, performing fermentation culture at 25-55℃ and 150-220 rpm for 5-10 days and then performing membrane filtration to obtain bio-oxidized graphite and (e) subjecting the bio-graphite oxide to supercritical carbon dioxide stripping and impurities removal to obtain the bio-graphene oxide.