▎ 摘　　要

NOVELTY - Preparation method of ethanol selective pervaporation composite membrane, involves (a) adding graphene oxide and polyvinylpyrrolidone into the ethanol aqueous solution, magnetically stirring, adding aqueous ammonia solution and ethyl orthosilicate, stirring at 25-35 degrees C for 5.5-6.5 hours to obtain a mixed solution, centrifuging the mixed solution, washing and drying to obtain graphene oxide-doped silica, (b) dissolving the graphene oxide-doped silica in n-heptane, adding 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, stirring, performing ultrasonic treatment, adding polydimethylsiloxane, and performing ultrasonic treatment to obtain a casting liquid, and (c) using a viscometer to monitor the viscosity of the casting solution, using a polyvinylidene fluoride microfiltration membrane as a support layer, coating the degassed film casting solution on the polyvinylidene fluoride microfiltration membrane with a scraper, placing at room temperature for 10-14 hours, and curing for 8-10 hours. USE - The method is used for preparation of ethanol selective pervaporation composite membrane which is used for separating and purifying ethanol (all claimed). ADVANTAGE - The method adopts pre-polymerization method to increase the viscosity of the polydimethylsiloxane matrix, and increases the addition amount of the silica-coated graphene oxide nanocomposite material in the composite film. The composite membrane has higher ethanol flux and selectivity, and has excellent ethanol separation ability. DETAILED DESCRIPTION - Preparation method of ethanol selective pervaporation composite membrane, involves (a) preparing graphene oxide-doped silica by adding graphene oxide and polyvinylpyrrolidone into the ethanol aqueous solution, magnetically stirring for 5-10 minutes, adding aqueous ammonia solution and ethyl orthosilicate, stirring at 25-35 degrees C for 5.5-6.5 hours to obtain a mixed solution, centrifuging the mixed solution, washing and drying to obtain graphene oxide-doped silica, (b) dissolving the graphene oxide-doped silica in n-heptane, adding 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, stirring for 40-80 minutes, performing ultrasonic treatment for 20-40 minutes, adding polydimethylsiloxane, and performing ultrasonic treatment for 20-40 minutes to obtain a casting liquid, and (c) using a viscometer to monitor the viscosity of the casting solution, using a polyvinylidene fluoride microfiltration membrane as a support layer, coating the degassed film casting solution on the polyvinylidene fluoride microfiltration membrane with a scraper, placing at room temperature for 10-14 hours, and placing in a vacuum oven at 70-90 degrees C for curing for 8-10 hours. INDEPENDENT CLAIMS are included for the following: (1) an ethanol selective pervaporation composite membrane, prepared by the above method; and (2) a method for separating and purifying ethanol, involving using the ethanol selective pervaporation composite membrane to separate and purify the ethanol aqueous solution.