Facile and effectual surface modification of polyacrylonitrile (PAN)-based ultrafiltration membranes via manipulating the synergistic interaction of dopamine and enzymes
Azar Asadi, S. Nazari, Foad Gholami, Mina Dolatshah
Abstract
A drastic improvement in the overall permeability and antifouling performance was observed for the polyacrylonitrile (PAN) ultrafiltration (UF) membrane by the co-incorporation of dopamine (DA), protease (E 1 ), and lipase (E 2 ) in a facile multi-step synthetic scheme. SEM was utilized to indicate the successful formation of modifying layers on the membrane surface , whereas ATR-FTIR and zeta potential were used to provide deeper insight into the membrane surface chemistry. AFM and contact angle were used to assess the membrane's surface roughness and hydrophilicity , respectively. The optimally modified membrane surface was found to be quite hydrophilic, as indicated by the water contact angle value (39.8 ± 0.8°), and water flux across the membrane of 78.09 ± 1.6 kg/m 2 ·h. Simultaneously, natural organic matter (NOM), including milk powder (MP), bovine serum albumin (BSA), and humic acid (HA), were efficiently removed, resulting in 99.9, 92.5, and 80.5 % removal efficiencies, respectively. Notably, the enzyme-immobilized membrane demonstrated outstanding antifouling performance as well as long-term stability. The dynamic anti-NOM fouling studies indicated that the surface modification was potentially capable of overcoming the tradeoff between membrane permeability and selectivity, resulting in FRR values of >90 %. The antibacterial properties of the surface-modified membranes against E. coli and S. aureus were also explored, and the optimal enzyme-immobilized membrane was found to be substantially antibacterial. Overall, this study aims to pave the way for the development of sustainable chemistry in designing innovative and highly efficient membranes.