(399t) Effect of Membrane Surface Chemistry on Water Permeance and Antifouling Properties

Fouling is one of the major challenges for the adoption of membrane technology for water purification. To mitigate the fouling, membrane surface can be chemically modified to reduce favorable interactions between the membrane and foulants, such as the coating with polydopamine (PDA). In this study, we systematically investigate the effect of various chemistries on the membrane surface on water permeance and antifouling properties. A versatile platform of membrane surface modification using PDA as a bio-glue is adopted. Specifically, membranes are co-deposited with dopamine and functional materials with different hydrophilicity. The functional materials containing thiol and/or acrylate groups can react with PDA through Michael addition to be grafted onto the surface. We have evaluated a series of acrylate-containing macromonomers including decyl acrylate, poly(ethylene glycol) methylether acrylate (PEGMEA), poly (1,3 dioxolane) acrylate (PDXLA), hexafluoroisopropyl acrylate (HFIPA), and a zwitterionic polymer (p(PBMA₁₆₀-co-DTMAEL₄₂)) on UF membranes. Effect of coating solution composition on the membrane surface hydrophilicity is studied. For example, when p(PBMA₁₆₀-co-DTMAEL₄₂), PDXLA, and PEGMEA are grafted, the water contact angle decreases because of the hydrophilic nature of these compounds. The coating layer is also validated using XPS. Effect of the surface modification on the pure water permeance is evaluated. The antifouling properties in the membranes are determined using a crossflow system and model foulants such as bovine serum albumin (BSA) with negative charge, lysosome with positive charge, and alginate. For example, the p(PBMA₁₆₀-co-DTMAEL₄₂)/PDA modified membrane exhibits less flux decline (32% reduction) that those coated by PDA (45% reduction) and unmodified one (53% reduction) after 4-h filtration with a BSA solution. We will systematically compare the effect of the surface chemistry on the water permeance and antifouling properties, aiming to derive the structure/property relationship.