(554d) Effect of Pattern Size Relative to Oil Droplet Size on Oil Fouling in Nanofiltration

Surface patterns are of interest to the membrane community after the success had in the biomedical industry with the Sharklet® pattern that mimics the form and function of shark skin. These surface patterns disrupt the fluid flow at the membrane surface, creating localized mixing that reduces fouling and make the membranes easier to clean. Fouling leads to a decrease in rejection and water transport through the membrane and will decrease the lifetime of the membrane. By adding surface patterns, we hypothesized that oil fouling will be decreased on the membrane surface. In this project, we investigated how the size of line-and-groove patterns affect fouling of ~10-micron sized oil droplets. The line-and-groove patterns are of 300 nm size, 10-micron size, and 50-micron size to look at patterns smaller than, equal to, and larger than the foulant size. Support membranes were patterned, and the nanofiltration (NF) polyamide layer was synthesized on top of the patterned supports. These patterned membranes are compared to commercially available NF membranes and non-patterned synthesized NF membranes. The membranes were challenged with three cycles of oil solution with cleaning and a water cycle after each oil solution. The flux recovery was calculated to determine the amount of reversible fouling. It was found that the pristine synthesized and nanopatterned sizes had the highest flux recovery of 91% and 89%, while the commercial and 10-micron had the lowest flux recovery of 78% and 83%. These results indicate that the pristine synthesized and nanopatterned membranes enhanced membrane cleanability.