Facile and controlled dual-step modification with enhanced anti-fouling performance in polyvinylidene fluoride membranes

Abstract

Water scarcity and pollution pose significant challenges, necessitating advancements in water treatment technologies. Among various solutions, ultrafiltration membranes, especially those crafted from polyvinylidene fluoride (PVDF), are favored for their mechanical robustness and chemical stability. However, their practical application is often limited by severe membrane fouling due to the inherent hydrophobicity of PVDF. This project introduces a straightforward, controlled method to enhance the anti-fouling properties of PVDF membranes, utilizing a blend of cellulose acetate (CA). The process involves a two-step modification of hydrolysis followed by quaternization, effectively increasing hydroxyl group presence and facilitating subsequent chemical reactions. The optimized membranes achieve a dynamic water contact angle of 0° within 30 s and maintain an electroneutral surface at pH 7.1. With a mean pore size reduction from 28.6 nm to 23.9 nm and an impressive drop in the irreversible fouling ratio from 36.9 % to 0.3 %, these modifications markedly improve the anti-fouling performance. This research demonstrates significant potential for enhancing the functionality of PVDF ultrafiltration membranes through post-fabrication modifications, offering significant benefits for water treatment applications.