Preparation Of PDMAEMA Modified PEBA/PSF Composite Membrane And Its Pervaporation Separation Performance

Pervaporation is a kind of green and high efficient membrane separation technology and its application field is more and more wide.It has a good application prospect in the field of dehydration of organic solvents,recovery of valuable organic compound and separation of organic compound,However,the well-known permeability/selectivity trade-off of polymeric membranes usually leads to a separation upper-bound with current generation of membranes.Therefore,in the process of pervaporation,it is important to take effective measures to improve its permeability.The preparation of high permeability and hydrophilic membrane with high permeability has become the focus of research.In order to improve the permeability performance of the membranes,the method of blending poly N,N-dimethylaminoethyl methacrylate(PDMAEMA)was used to improve the water permeability of polyether block amide(PEBA)/polysulfone(PSF)composite membrane.PDMAEMA-PEBA/PSF composite membrane was prepared by quaternization crosslinking reaction to fix water soluble PDMAEMA in the membrane to avoid dissolution,and the membrane was used for pervaporation ethylene glycol dehydration.The effects of parameters(including blending ratio and crosslinking conditions)on membrane structure and permeability selection performance were investigated.The experimental results showed that after adding PDMAEMA,the surface hydrophilicity of the membrane increases,the roughness increases,and the contact angle decreases.when the polymer content is 10g/L and the content of PDMAHMA 15-30%,the permeability of blend membrane is optimal,compared with PEBA/PSF composite membrane,the water flux inereased by about 80%,water/glycol separation factor increased by about 40%.And pervaporation performance of PDMAEMA/PEBA-PSF composite membrane can be controlled by controlling the kind of crosslinking agent,crosslinking agent concentration,crosslinking time.On this basis,a method of preparing E-PDMAEMA-PEBA/PSI" composite membrane under electric field was put forward,and the influence of electric field on the structure and permeability selectivity of composite membrane was studied.The results showed that in the process of membrane preparation,the electric field on both sides of the membrane was applied,the content of the charge group on the surface of the membrane was increased and the hydrophilicity was increased.The water flux of membrane prepared under the electric field increased significantly compared with that without electric field.When the blending content was 15-30%,the flux increased significantly,and the membrane flux increased by 80%compared with that without electric field,and the separation factor increased significantly,which increased by about 35%.By blending and electric field treated membranes showed excellent performance in improving permeability,It can also improved the separation performance while improving the permeation flux.It showed that the two modified methods of blending PDMAEMA modification and external electric field modification can improved the permeation selectivity of membrane.