Preparation And Separation Properties Of Graphene Oxide Films

Membrane technology is an efficient and energy-saving separation technology.GO is considered to be the preferred material for the preparation of the next generation separation membrane due to its natural nanostructure.However,due to the self-absorption of water,the application has been limited by the problem of low strength and expansion of channels in humid environment.Physical cladding and chemical crosslinking are effective methods to overcome the problem of low strength of GO.Physical cladding can effectively limit the spacing of GO.Therefore,the key to improve the separation efriciency of the GO membrane is to realize the tight arrangement between nano-plates.In this article,self supporting GO membrane was prepared through interface self-assembly,which was realized through GO nanoplates dehydrating step by step to realize,more tight interlayer structure.Compared with the ordinary GO membrane,the interlayer spacing was reduced by about 0.05nm.Self-assembled membrane separation performance and penetration performance tcst results show that under the condition of no obvious change in the chemical enviroment.60 ? and 70 ? self-assembly GO membrane showed a higher separation cffciency and penetration rate,of whih the reason is that its strLucture is more neat,benifiling to the penetration of water molcecules and and ionic sieving.Chemical crosslinking is an important method to improve the strength of GO film,but chemical crosslinking can lead to the decrease of hydrophilic and pcrmeability of GO membrane.ln this paper,ccellulose accete membrane(CA)for support and the urea(UR)for crosslinking agent,and sodium hydroxide(NaO11)for catalyzer,the membrane was prepared by vacuum fitration method.The result shows that the GO reduction degree was low when take UR crosslinking agent,and the hydrophilicity of the GO was maintained to a certain extent,and its water flux was not significantly reduced.Because of the high oxygen content and the introduction of the carbonyl group in UR,the "free space" in the GO-UR/CA membrane was smaller,which enhanced the physical sieving effect and enhanced the ions rejection rate.This discovery provides a new idea for the preparation of efficient GO separation membrane.