(559a) Flux and Antifouling Performance of Bioinspired Liquid-Infused Membranes

Over the past few decades, the use of ultrafiltration (UF) membranes for water treatment and wastewater reuse has increased. However, the accumulation of bacteria on the surface of the membrane and blocking of the pores significantly reduces process productivity. Thus, eliminating biofouling during membrane-based separations is a major challenge. To address this problem, we have developed a novel approach to membrane technology inspired by the pitcher plant, called liquid-infused membranes (LIMs). Here, we added a biocompatible, chemically inert, omniphobic perfluoropolyether coating liquid to commercial polyvinylidene fluoride (PVDF) membranes and explore the flux and antifouling properties of the composite membranes. Two lubricating oils with varying viscosities namely, Krytox™ 103 (K103) and Krytox™ 107 (K107) were explored. First, the concentration of oil needed to form a continuous fluid layer on the membrane surface was successfully confirmed using the aqueous crystal violet stain, which only stained areas of the membrane that lacked the lubricating oil. Variable pressure scanning electron microscopy (VP-SEM) micrographs visually confirmed that the lubricant was inside the membrane pores. Next, pure water permeability (PWP) experiments were conducted using a dead-end testing to investigate membrane performance. On applying a transmembrane pressure (1 - 4 bar), we observed a very high flux post-compaction for bare PVDF membranes but when oil was immobilized a lower flux was obtained. The liquid-infused membranes exhibited a consistent PWP over 10 cycles, indicating the formation of a stable liquid layer within the membrane’s structure. Static antifouling assays conducted using Escherichia coli K12 demonstrated that there was a significant decrease in microbial attachment for PVDF membranes infused with K103 and K107. These findings suggest that liquid-infused membranes hold potential in membrane-based water treatment and other industrial processes.