Nanofiber Composite Membrane Prepared by Electrostatic Printing Assisted Interfacial Polymerization for Seawater Desalination

A method of preparing nanofiber composite membrane was proposed by electrostatic spray print assisted interfacial polymerization for seawater filtration. Polyacrylonitrile (PAN) nanofiber substrate was intercalated via polyether amine (PEA), piperazine and triformyl chloride. PAN nanofiber was soaked in aqueous solution that piperazine and PEA were uniformly adsorbed on the substrate surface, firstly. The excess aqueous solution was dried with filter paper, and then organic triformyl chloride was introduced into the surface of PAN substrate to react with aqueous phase, then thin film nanofiltration composite (TFNC) with good filtration performance was prepared. The filtration performance of TFNC composite membrane with PEA concentration was studied. The microstructures were characterized by field emission scanning electron microscopy and atomic force microscopy, interfacial polymerization with fourier transform infrared absorption spectrometer, hydrophilicity with contact angle measuring instrument and charge property of the composite films with Zeta potentiometer. Four kinds of inorganic salts were selected to test the filtration performance of TFNC membrane by dead-end filtration system. PAN solution can be electrospun on the surface of roller to form a uniform film surface structure. The surface of the thin films prepared with PAN transparent solution was smooth with a printing concentration of 8wt.% under 20 kV electrostatic high pressure. When PEA concentration was 4.5wt.%, the contact angle of TFNC composite membrane was the smallest, reaching 47.5°. The filtration performance test of four inorganic salts showed that at 25°C and 0.4 MPa, when PEA concentration was 3.0wt.%, the water flux of the membrane could reach 41.5 L/(m2·h), and the interception rate of NaCl was low (18.6%), but the interception rate of anionic dye MYB was the highest (95.4%). Electrostatic spray prin assisted interfacial polymerization can prepare nano-fiber composite membrane simply and effectively, and obtain smooth, uniform hydrophilic surface. The separation performance of composite nanofiltration membrane can be adjusted by changing the concentration of PEA, and the salt from seawater can be remove effectively, which has strong development potential. © 2022, Chongqing Wujiu Periodicals Press. All rights reserved.