3D Printed Fouling-resistant Composite Membranes

Fouling remains a long-standing unsolved problem that hinders the widespread use of membrane applications in industry. This article reports the use of numerical simulations coupled with extensive materials synthesis and characterisation to fabricate fouling-resistant 3D printed composite membranes. The membranes consist of a thin polyethersulfone selective layer deposited onto a 3D printed flat and double sinusoidal (wavy) support. Fouling and cleaning of the composite membranes were tested by using bovine serum albumin (BSA) solution in a cross-flow ultrafiltration setup. The transmembrane pressure was regulated at 1 bar and the cross-flow Reynolds number (Re) varied between 400 and 1000. In comparison to the flat membrane, the wavy membrane showed superior performance in terms of pure water permeance (PWP) (10% higher) and permeance recovery ratio (87% versus 53%) after the first filtration cycle at Re = 1000. Prolong testing showed that the wavy membrane could retain approximately 87% of its initial PWP after 10 complete filtration cycles. This impressive fouling-resistant behaviour is attributed to the localised fluid turbulence induced by the 3D printed wavy structure. These results show that not only the lifetime of membrane operations could be favourably extended, but that the operational costs and environmental damage of membrane-based processes could also be significantly reduced.