Study On Preparation And Separation Performance Of Functional Two-dimensional Membrane

Membrane separation technology has the advantages of low energy consumption and continuous operation.It has a wide application prospect in chemical industry and other fields.Traditional polymer membranes have"trade-off"effect.Therefore,the development of new membrane materials is expected to promote the further development of membrane separation technology.The two-dimensional nano channel membrane has orderly and regular transmission channels,which can significantly reduce the mass transfer resistance and improve the separation performance.The filling elements of two-dimensional membrane materials determine the properties of two-dimensional nanochannel films.Based on this,this paper summarizes the research progress of two-dimensional membrane layered nanochannel membrane and through-channel nanochannel membrane,and their application in the field of separation.A two-dimensional based on MXene-pillar[5]arene composite membrane and chiral COFs filled mixed matrix membrane was constructed to realize the efficient treatment of dye wastewater and separation of chiral enantiomers.The relevant research contents and conclusions are as follows:（1）Two-dimensional MXene-pillar[5]arene complex membrane was used to filter dye wastewater.MXene nanosheets were prepared by selective etching.Monocarboxyl pillar[5]arene was designed and synthesized,and MXene-P5composite nanosheets were prepared by condensation reaction.An electrochemical sensor based on MXene-pillar[5]arene was developed to detect organic dye molecules in water with high sensitivity,and the detection limit of methyl orange was up to0.05μm.MXene-pillar[5]arene composite two-dimensional membrane was obtained by vacuum assisted self-assembly strategy,which further realized efficient separation of dyes in water.The results showed that the rejection rate of the new composite two-dimensional membrane to macromolecular organic dyes such as methylene blue and crystal violet was 100%,and the water flux was up to 792.1 L m^-2 h^-1 bar^-1.The MXene-pillar[5]arene composite two-dimensional membrane prepared in this study can detect and separate dye molecules in sewage at the same time,which is expected to achieve the purpose of water purification and provides a new strategy for the design of functional two-dimensional membrane materials.（2）Two-dimensional chiral COFs membrane was used for chiral separation of enantiomers.Chiral borate covalent organic framework materials（CCOFs）were prepared by 1,3-cycloboridation of（2R,3R）-1,1,4,4-tetraphenylbutyltetraol derived from tartaric acid with benzene 1,3,5-triborate.The constructed CCOFs had regular cavity structure and pore channels,and the high compatibility between CCOFs and polysulfone（PSF）was utilized to construct the mixed matrix membrane（MMMs）based on CCOFs material to achieve efficient chiral separation of chiral substances.The results indicated that CCOFs MMMs showed excellent chiral separation effect for the two chiral substances,and the enantiomer excess（ee）value more than 99%.The CCOFs MMMs constructed in this study has great development potential in the field of chiral separation of chiral substances,and is expected to achieve efficient and accurate separation of chiral substances.