▎ 摘　　要

NOVELTY - Preparing mixed graphene oxide nanofiltration membrane comprises (i) dispersing graphene oxide, centrifuging, then taking the supernatant for drying and quantifying to obtain small size graphene oxide, re-dispersing the precipitate at the bottom, centrifuging, drying and quantifying the obtained precipitate to obtain large-size graphene oxide, (ii) configuring the large-sized graphene oxide with pure water into a large-sized graphene oxide dispersion, and configuring the small-sized graphene oxide with pure water into a small-sized graphene oxide dispersion, (iii) configuring the large-sized graphene oxide dispersion and the small-sized graphene oxide dispersion into a mixed graphene oxide dispersion in a certain ratio, and (iv) suction-filtering the mixed graphene oxide dispersion onto a polyvinylidene fluoride support membrane under vacuum, and drying to obtain a mixed graphene oxide nanofiltration membrane. USE - The nanofiltration membrane is useful in wastewater treatment (claimed). ADVANTAGE - The mixed graphene oxide nanofiltration membrane: reduces the interlayer distance; increases the flow path; improves the salt interception efficiency; and has strong mechanical stability, which enhances the retention ability and long-term stability of small molecules of the dye. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for mixed graphene oxide nanofiltration membrane prepared by above method.