▎ 摘　　要

NOVELTY - Preparing graphene sheet having vertically oriented film material comprises e.g. (i) preparing graphene oxide solution, (ii) adding antifreeze agent into graphene oxide solution and stirring, (iii) pouring mixed solution into polytetrafluoroethylene container, and placing at bottom of polytetrafluoroethylene container on liquid nitrogen surface in direction of bottom-up directional freezing, (iv) freeze-drying hydrogel of graphene sheet oriented vertically oriented film material, and (v) annealing airgel of graphene sheet oriented vertically oriented film material. USE - The film material is useful in desalination, acid solution, alkaline solution or heavy metal solution for water cleaning (claimed). ADVANTAGE - The method is simple, easy to operate, and is suitable for large-scale production. DETAILED DESCRIPTION - Preparing graphene sheet having vertically oriented film material comprises (i) preparing graphene oxide solution, (ii) adding antifreeze agent into graphene oxide solution and stirring to obtain homogeneous solution, (iii) pouring mixed solution into polytetrafluoroethylene container, and immediately placing at bottom of polytetrafluoroethylene container on liquid nitrogen surface in direction of bottom-up directional freezing to obtain graphene sheet of vertically oriented film material, (iv) freeze-drying hydrogel of graphene sheet oriented vertically oriented film material at -45 to -55 degrees C for 48-72 hours to obtain airgel of graphene sheet with vertically oriented film material, and (v) annealing airgel of graphene sheet oriented vertically oriented film material at 150 -200 degrees C for 1-3 hours under argon atmosphere, and then annealing at 600-1000 degrees C for 2-4 hours to obtain final product, where antifreeze agent is methanol, ethanol or n-propanol.