Natural organic matter removal and fouling resistance properties of a boron nitride nanosheet-functionalized thin film nanocomposite membrane and its impact on permeate chlorine demand

Nanofiltration (NF) is an attractive surface water treatment option for the enhanced removal of natural organic matter (NOM) to comply with the regulations of potentially toxic disinfection by-products (DBPs) formation. However, organic fouling has remained an unresolved issue which makes the process less cost-effective. To address this problem, the current study reports on the fabrication of a new thin film nanocomposite (TFN) membrane incorporated with and decorated by amine-functionalized boron nitride BN(NH2) nanosheets. Physicochemical investigations revealed 60 and 40 % enhancement in hydrophilicity and negative charge density of the modified membranes, respectively, which translated into 69 % improvement in flux as well as boosted NOM removal and fouling resistance compared with control counterparts. Additionally, the modified membranes exhibited a better filtration performance under detrimental solution chemistry conditions of low pH and high Ca2+ concentration. Liquid chromatography coupled with organic carbon detection (LC-OCD) profiles and fluorescence excitation emission matrices (FEEM) demonstrated the capability of the modified membranes in removing humics and lower molecular-sized compounds from water as opposed to moderate removals achieved in a conventional water treatment plant. Finally, AQUASIM simulations showed the lower chlorine demand of the NF-treated water which can reflect on its decreased DBPs formation potential.