Removal of steroid hormone micropollutants by UF-PBSAC composite in presence of organic matter

Abstract The present study investigated ultrafiltration (UF) membranes in a combination with a polymer-based spherical activated carbon (PBSAC) thin layer on the permeate side (UF-PBSAC) to remove the steroid hormone micropollutant (MP) estradiol (E2) from water. The impact of dissolved organic matter on the process was assessed using two types of water: one synthetic water containing humic acid (HA) and one natural water from Tanzania (Maji ya Chai River in Swamp). In both cases, only a minor impact of organic matter on the adsorption of MP was observed proving that the permeate side PBSAC layer is an effective polishing step in MP removal. The significance of UF molecular weight cut off (MWCO) was further investigated. The removal of the MP by UF-PBSAC was generally not affected by the MWCO even though a higher organic matter rejection could be achieved for lower MWCO membranes. For UF MWCOs lower than 10 kDa the UF-PBSAC is effectively removing both the MP and a major fraction of organic matter. Static adsorption investigations highlighted a significant difference in the adsorption kinetics between organic matter and MP. This can explain the preferential adsorption of the MP on PBSAC even in presence of organic matter, and hence an absence of competition.