Study On Hydrophilic Modification Of Polymer Nanofiltration Membrane And Its Performance

Polysulfone membranes have great application prospects in commercial nanofiltration membranes.They have gradually become mainstream in the fields of food,industry,medical treatment and water treatment because of their good stability and excellent mechanical properties.However,the problems of membrane fouling,low flux,and decay of membrane flux in polysulfone membranes have greatly restricted the application of nanofiltration technology.In response to this problem,mussel-inspired chemistry was used to modify the surface of the polysulfone membrane to improve the hydrophilic performance,the membrane flux,and anti-pollution of polymer membrane.In this paper,tert-butyl hydroperoxide（TBHP）-dopamine（DA）-tris-hydroxy-methylaminomethane（Tris）buffer was used to prepare hydrophilic nanofiltration by depositing polydopamine（PDA）on the surface of polysulfone membrane（PSF）membrane.In this paper,the influence of the amount of TBHP,the p H of the buffer and the time of the buffer on the membrane on the hydrophilic and oleophobic properties,morphology and water flux of the membrane were studied.The research results show that TBHP-DA polysulfone modified membrane exhibits good hydrophilic properties,and the membrane flux is significantly enhanced.With the amount of TBHP increasing,the hydrophilic properties and water flux of the modified membrane increase first and then decrease;With the p H of the empty buffer increasing,the hydrophilic properties and water of the modified membrane also increases and then decreases;With the time for the buffer to process the membrane increasing,the hydrophilic properties of the membrane and the water flux gradually increase and tend to stabilize.Next,using FTIR,XPS,water-oil contact angle measuring instrument,SEM,AFM and other methods to characterize the element composition,structure,morphology,hydrophilicity,stability and permeability of PSF membrane surface and modified PSF membrane surface.The results show that while p H=8.5 and the amount of TBHP added is 800（?）L,the water contact angle of the PSF membrane reduced from 52°to 13°,and the oil contact angle increased from 142°to165°.A hydrophilic modified membrane is obtained.The pure water flux is 91.3 L m^-2h^-1,which is 170.4%higher than that of the PSF-based membrane,and the rejection rate is 90.7%.After ultrasonic vibration,the water contact angle only drops by 3.1°,showing good stability.In this paper,bovine serum albumin（BSA）solutions were filtered,and the anti-fouling performance of the polysulfone modified membrane under optimized conditions was studied and analyzed.The results show that the TBHP-DA-800 modified membrane shows excellent anti-pollution ability,and the flux recovery rate reaches 91.6%.This paper provides a new research method for studying the hydrophilic modification of polysulfone nanofiltration flat membrane,and also provides a new research direction for the construction of high-performance polymer nanofiltration membrane.