A facile modification approach for polyacrylonitrile-based UF hollow fiber membrane utilizing polyacrylonitrile-g-poly(vinyl alcohol) graft copolymer

Facile blending approach utilizing amphiphilic copolymers has received enormous attention from researchers owing to their unique self-organizing behaviour that can improve membrane structure and separation properties. This paper discusses the effect of the amount of acrylonitrile (AN) monomer added during polyacrylonitrile-g-polyvinyl alcohol (PAN-g-PVA) copolymer synthesis and its relationship to the properties and performance of PAN-based ultrafiltration (UF) hollow fiber membrane. The hollow fiber membranes were characterized using atomic force microscope, scanning electron microscope, X-ray photoelectron spectroscope and contact angle goniometer, in addition to performance evaluation with respect to protein rejection and antifouling resistance. As for the UF experiments, the membrane incorporated with copolymer of highest monomer composition achieved the highest pure water flux (178.76 L/m².hr) coupled with good rejection of bovine serum albumin (BSA) and albumin from chicken egg (at least 83 %) when tested at 1 bar. The promising results are mainly due to the changes in the membrane morphological properties, surface roughness, surface chemical composition and hydrophilicity upon the addition of the copolymer. In terms of anti-fouling performance, generally, blend membrane prepared from copolymer of lowest amount of monomer produced good flux recovery for all proteins (74 %, 67 % and 62 % during BSA, albumin from chicken egg and trypsin) filtration due to the enrichment of PVA on membrane surface and its low surface roughness. The experimental results offer an important insight into the relationship between amount of monomer added during graft copolymer synthesis and membrane properties and performance, providing valuable information for high performance UF membrane for fouling mitigation especially in the area involving proteinaceous solution.