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 chemically inert, perfluoropolyether coating liquid to commercial polyvinylidene fluoride (PVDF) membranes and explored the flux and antifouling properties of the composite membranes. Two lubricating oils with varying viscosities namely, Krytoxô 103 (K103) and Krytoxô 107 (K107) were investigated. First, pure water permeance experiments were conducted using a dead-end stirred cell to investigate membrane performance. After applying high pressure (1 – 4 bar), we observed a very high flux post-compaction for bare PVDF membranes; when the membranes were infused with oil, as expected, a lower flux was obtained. The liquid-infused membranes exhibited a consistent pure water permeance over 10 cycles, indicating the formation of a stable liquid layer within the membrane. Static antifouling assays conducted using Escherichia coli K12 demonstrated that there was a significant decrease in microbial attachment for PVDF membranes infused with K103 or K107. These findings suggest that liquid-infused membranes hold potential in membrane-based water treatment and other industrial processes.