Removal of contaminants of emerging concern by membranes in water and wastewater: A review

This review summarizes comprehensive recent studies on the removal of contaminants of emerging concern (CECs) by forward osmosis (FO), reverse osmosis (RO), nanofiltration (NF), and ultrafiltration (UF) membrane treatments, and describes important information on the applications of FO, RO, NF, and UF membranes in water and wastewater (WW) treatment. The main objective of this review was to synthesize findings on membrane treatments of CECs in water and WW, and to highlight upcoming research areas based on knowledge gaps. In particular, this review aimed to address several key parameters, including the physicochemical properties of CECs (solute molecular weight/size/geometry, charge, and hydrophobicity), water quality conditions (pH, solute concentration, temperature, background inorganics, and natural organic matter), and membrane properties and operating conditions (membrane fouling, membrane pore size, porosity, charge, and pressure) that influence the removal of CECs during membrane filtration. Future research directions regarding membrane treatment for the removal of CECs from water and WW are also discussed.