A combined interfacial polymerization and in-situ sol-gel strategy to construct composite nanofiltration membrane with improved pore size distribution and anti-protein-fouling property

Abstract Pore size distribution is crucial for the application of nanofiltration membrane in size-selective separation of industrial fluids. In this work, a novel combined interfacial polymerization (IP) and in-situ sol-gel strategy was proposed to fabricate composite nanofiltration membrane with narrow pore size distribution. Aqueous solution of piperazine and polyvinyl alcohol (PVA) was employed to perform interfacial polymerization with organic solution of trimesoyl chloride and tetraethyl orthosilicate (TEOS) on porous support. The non-reactive additive TEOS within the interfacially synthesized selective separation layer was then employed to perform sol-gel. The space-limited hydrolysis and condensation of TEOS molecules and their chemical bonding with PVA molecules were confirmed by analyzing membrane physico-chemical property and were found to be effective in tuning mean pore diameter, narrowing the pore size distribution and thus enhancing membrane perm-selectivity. Compared to those of membrane PA1 with similar mean pore size fabricated by only IP technique, the water permeability and rejection ratio of PEG1000 to raffinose (RPEG1000/Rraffinose) of membrane PA-TEOS0.5 fabricated by combined IP and sol-gel technique were higher by 25.0 and 20.1%, respectively. Moreover, static adsorption and dynamic deposition tests using aqueous bovine serum albumin solution proved that in-situ sol-gel process could endow the membrane with better protein fouling resistance.