Preparation And Performance Of Cyclodextrin-based Polymer Ultrafiltration Membrane

Polysulfone is a kind of the common ultrafiltration membrane materials.There are problems such as poor contamination resistance and short membrane life in practical applications because of its hydrophobic nature.Therefore,the hydrophilic modification of polysulfone ultrafiltration membrane is an essential step in the preparation of high performance ultrafiltration membrane.The optimum process parameters for preparation of polysulfone ultrafiltration membranes were obtained and the effects of different additives on the structure and properties of ultrafiltration membranes were discussed in this paper.In this study,polysulfone?PSF?was used as the base membrane material,N,N-dimethylacetamide?DMAc?as the organic membrane solvent,polyethylene glycol-400?PEG-400?as the porogen and Tween-80 as the surfactant.?-cyclodextrin,nano-ZnO and nano-TiO₂ were used as the blend modifiers.Four different types of ultrafiltration membranes were prepared by immersion precipitation phase transformation method.The effects of membrane material content,the type and content of porogen,surfactant concentration,additive content,stirring temperature,and coagulation bath temperature on the performance of ultrafiltration membranes were investigated.The optimal film processing parameters of the four kinds of membranes were finally determined through a series of experiments.And the surface morphology,cross-section structure,surface roughness,contact angle and the resistance increase coefficient of membranes were analyzed.The water flux,the rejection rate and the membrane resistance increase coefficient of the ultrafiltration membranes were measured with a laboratory-made membrane performance evaluation device.The surface and cross-section structure of the membrane was measured with a scanning electron microscope.The surface roughness of the membrane was measured with an atomic force microscope.The contact angles of various membranes with water were measured with a contact angle tester,and the bacteriostatic conditions of various membranes were tested by the inhibition zone test method.?1?The influence of various factors on the performance of ultrafiltration membranes were studied through a series of experiments.And the optimal membrane production process parameters for traditional polysulfone ultrafiltration membranes are as follows:the optimal content of polysulfone in the membrane material is 14 wt%,the optimal polyethylene glycol type is polyethylene glycol-400,the optimum content of surfactant Tween-80 is 1.0 wt%,the best stirring temperature is 80?and the optimal coagulation bath temperature is 30?.The water flux of the traditional polysulfone ultrafiltration membrane prepared under this condition is 313.45 L/m²?h,the retention rate of bovine serum albumin is 90.35%,the resistance increase coefficient of the membrane is 1.11,the contact angle is 87.3oand the roughness of the membrane surface is 11.320 nm.The supporting layer of the ultrafiltration membrane presents finger pore structure.?2?The influence of various factors on the performance of ultrafiltration membrane was studied through a series of experiments.And then the optimal process parameters for polysulfone/?-cyclodextrin hybrid ultrafiltration membranes were obtained.The optimum content of polysulfone is 14 wt%,the optimum content of modified additive?-cyclodextrin is1.5 wt%,the optimum concentration of surfactant Tween-80 is 1.0 wt%,the optimum stirring temperature is 80?and the optimal coagulation bath temperature is 25?.The water flux of the polysulfone/?-cyclodextrin hybrid ultrafiltration membrane prepared under this condition is 337.28 L/m²?h,the rejection of bovine serum albumin is 87.45%,the membrane resistance increase coefficient is 0.76 and the contact angle is 80.7o.The roughness of the membrane surface is 12.636 nm.The performance of polysulfone/?-cyclodextrin hybrid ultrafiltration membranes is significantly better than that of unmodified membranes.?3?The influence of various factors on the performance of ultrafiltration membrane was studied through a series of experiments.And then the optimal membrane process parameters of polysulfone/?-cyclodextrin/nano-ZnO hybrid ultrafiltration membrane were obtained.They are as follows:the optimal content of polysulfone is 15 wt%,the optimum content of modified additive?-cyclodextrin/nano-ZnO is 2.0 wt%,the optimal concentration of surfactant Tween-80 is 2.0 wt%,the best stirring temperature is 80?,and the optimal coagulationbathtemperatureis30?.Thepurewaterfluxofthe polysulfone/?-cyclodextrin/nano-ZnO hybrid ultrafiltration membrane prepared under this condition is 345.79 L/m²?h,the rejection of bovine serum albumin is 89.58%,the coefficient of increase of membrane resistance is 0.63,the contact angle is 73.2oand the roughness of the membrane surface is 24.090 nm.The membrane pores of the hybrid membrane prepared under these conditions are well-finger pore structure,and its water flux and contamination resistance are greatly improved.?4?The optimal process parameters for polysulfone/?-cyclodextrin/nano-TiO₂ hybrid ultrafiltration membranes are obtained through a series of experiments about the effects of various factors on the performance of ultrafiltration membranes.The optimal content of polysulfone is 15 wt%,the optimum content of modified additive?-cyclodextrin/nano-TiO₂ is2.0 wt%,the optimal concentration of surfactant Tween-80 is 2.0 wt%,the best stirring temperature is 70?,and the optimal coagulation bath temperature is 30?.The water flux of the polysulfone/?-cyclodextrin/nano-TiO₂ hybrid ultrafiltration membrane prepared under this condition is 349.59 L/m²?h,the rejection of bovine serum albumin is 91.32%,the coefficient of increase of membrane resistance is 0.65,the contact angle is 75.8oand the roughness of the membrane surface is 11.192 nm.The hybrid ultrafiltration membrane prepared under these conditions is the best performing ultrafiltration membranes among the four kinds of membranes.