Effects of co-existence of organic matter and microplastics on the rejection of PFCs by forward osmosis membrane

Abstract Perfluorinated chemical (PFC)-based materials have been widely applied in industry. In this study, the influence of PFCs on the physicochemical properties of membranes and that of the co-existence of organic matter and microplastics on the removal rate in the process of forward osmosis (FO) was examined. The water flux, reverse salt flux, and rejection of PFCs were evaluated under w and w/o contaminants. The lowest rejection rates of PFCs in FO membranes were observed to be 92.2% and 90.4% for FO-TFC and PA-Aqua FO membranes, respectively. The main rejection mechanism of the FO membrane is the sieving effect (p-value: PA-TFC-0.015, PA-Aqua-0.002) based on molecular volume, which is more dominant than the electrostatic repulsive force and hydrophobic interaction, the major rejection mechanisms of existing trace contaminants. In addition, we observed that the effects of co-existing pollutants in raw water have an insignificant effect on the rejection of PFCs because of the physical and chemical stability of PFCs. According to the results of this study, using the FO membrane, PFCs can effectively control not only their self-existence but also when contaminants co-exist with them in water bodies.