Development of Novel Low Biofouling Membranes for Use in Water Filtration Applications

Water scarcity is fast becoming a pressing issue around the world, in particular Qatar which is particularly vulnerable to future water shortages due to low precipitation levels and a rapidly booming human population. The reliance on desalination and ground water extraction pose challenges and may prove unsustainable in the future. In order to circumvent this issue, Qatar has set out a government mandate as part of its 2030 Vision to reuse at least 50% of all treated sewage effluent (TSE) it produces. In this work, locally obtained TSE had its bacterial community identified and alignment results indicated the presence of several pathogenic bacterial species, which brought the safety of using TSE in urbanized areas into question. Owing to the fact that the TSE produced in Qatar is treated to tertiary level at best, the need for advanced treatment to further polish the produced TSE has recently gained traction. Membrane filtration systems offer one such option; however, since membranes are heavily prone to biofouling processes, the need for low biofouling membranes remains a priority. To that end, a selection of low biofouling polymeric membranes were fabricated. Polysulfone (PS) membranes incorporating arabic gum (AG), polyethersulfone (PES) membranes incorporating in-house synthesized graphene oxide (GO) with AG and PES membranes with oxidized multiwalled carbon nanotubes (OMWCNT) with AG were extensively characterized by means of chemical and physical testing. The composite membranes showed superior surface hydrophilicity and increased surface charge with smoother surfaces compared to their respective neat membranes. These hallmark features of low biofouling membranes were implicated in conferring resistance to bacterial colonization. The novel composite membranes filtered bacterial suspensions and real TSE over prolonged periods without experiencing a notable decline in flux and were effective in the complete removal of bacteria from the permeates produced. These novel low biofouling membranes provide a promising solution to the "Achilles heel" of membrane technology, where their application in water filtration processes can be realized.