Artificial Photosynthesis Lab

Water scarcity is an escalating global challenge, leaving billions without consistent access to clean water. Desalination, particularly through reverse osmosis (RO), has become a critical method of producing fresh water from saline sources. However, thin-film composite (TFC) polyamide (PA) RO membranes, the industrial desalination standard, have a high propensity for biofilm formation, which leads to biofouling, reducing efficiency and increasing energy demand. Ozone disinfection is a simple, effective method to control biofilm development; however, PA membranes undergo chemical degradation when exposed to oxidizing disinfectants, even at very low concentrations. This work presents a novel approach to enhancing the durability of TFC-PA membranes against ozone. This was achieved by applying ultrathin alumina coatings via atomic layer deposition (ALD) on the membrane surface, creating a protective layer that provides active and passive defense against oxidative damage. The thin-film alumina-coated membrane at optimal coating demonstrated 5-fold higher tolerance to ozone exposure than uncoated membranes. They also maintained stable water permeate flux and salt rejection after prolonged filtration and effectively prevented biofilm formation. These findings offer a promising pathway to enhancing the sustainability of RO membranes by addressing critical barriers to their long-term desalination performance, thereby contributing to addressing the problem of global water scarcity.