▎ 摘　　要

NOVELTY - Composite separation membrane, comprises poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) nanofiber membrane, and graphene layer compounded on PVDF-HFP nanofiber membrane. The PVDF-HFP nanofiber membrane contains carbon nanotubes. USE - The composite separation membrane is useful in membrane distillation (claimed) and for separating non-volatile solute water, seawater desalination, ultra-pure water preparation, waste water treatment. ADVANTAGE - The composite separating membrane has more excellent mechanical property and hydrophobic property, and stable film material property. The method is simple and easy to operate, suitable for large area industrial popularization and application. The obtained film property is stable, belonging to the multifunctional environment-friendly material. The carbon nano-tube is more suitable for the arrangement of the film fiber, realizing uniform directional distribution, so that the reinforcing effect is more excellent. The graphene with good hydrophobicity property and high pollution resistance is directionally arranged on the surface of the nano fiber separation film, modifying the existing separation film. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a preparation method of composite separation membrane.