Structural Design And Application Of High-throughput Polypyrrole Solvent-resistant Nanofiltration Memberane

With the rapid development of industry,the use and discharge of organic solvents have increased year by year,and direct discharge of organic solvents has caused serious waste of resources and environmental threats.Therefore,the recovery of organic solvents is of great significance for saving resources and achieving sustainable development.Compared with traditional solvent extraction methods,membrane separation technology has the advantages of high degree of automation and high separation efficiency,and is considered as an effective method to solve the problem of solvent recovery.Among them,solvent-resistant nanofiltration is a technology for separating 200-2000 g/mol organic solutes,which can effectively recover the organic solvents involved in the process of medicine and small molecule organic synthesis.However,the lack of high-efficiency permeable membrane materials,especially the high-efficiency permeable membrane materials with both polar and non-polar solvents,has limited the scale application of this technology.In this subject,based on molecular design,polypyrrole with a conjugated structure and polar groups was selected as the selection layer.The introduction of new nanoparticles further increased the affinity for solvents and greatly improved the penetration of organic solvents by solvent-resistant nanofiltration membranes.Performance provides new ideas for the design of new highthroughput solvent-resistant nanofiltration membranes.This topic optimized the preparation of polypyrrole mixed matrix membranes(MMMs)under different conditions.The types of pyrrole,pyrrole concentration,ferric chloride concentration,and polymerization time were investigated.The optimal preparation conditions of the polypyrrole composite membrane were determined.At this time,the permeance reached 8.8 L/MHB and the retention rate of Bengal rose red was as high as 99%.UiO-66 porous nanoparticles were synthesized and chemically grafted to further increase the dispersibility of the nanoparticles.The effects of the addition amount of UiO-66 and the types of UiO-66 on the separation performance of MMMs were investigated.Studies show that the addition of 0.05% grafted UiO-66 can increase the ethanol permeation flux of MMMs by 513%(53.9 L/MHB),and the retention performance is basically unchanged.This subject further characterizes the structure of the polypyrrole mixed matrix membrane and systematically studies the separation performance of the membrane.Studies have shown that the introduction of nanoparticles effectively increases the porosity of the separation membrane and the affinity between the membrane and the organic solvent.The effect on the pore size of the separation membrane is small,which greatly increases the permeability of the mixed matrix membrane to the solvent,and the retention performance of the solute molecules remains unchanged.The MMMs have a permeance of 244.0 L/MHB for pentane,172.9L/MHB for hexane flux,and 58.1 L/MHB for water flux,with a cut-off molecular weight of less than 400 Da.Therefore,the high-throughput polypyrrole mixed matrix membrane prepared in this study has potential application prospects in the fields of organic solvent recovery and chemical and pharmaceutical industries.