Preparation and characterization of a high flux nanofiltration polyamide hollow fiber TFC membrane for drinking water production

In this study, a nanofiltration (NF) polyamide hollow fiber thin film composite membrane with a low rejection and a high flux was prepared in consideration of the “trade-off” relation between salt rejection and permeate flux of the membrane. The membrane was able to retain the beneficial minerals in tap water while keeping the body healthy. The membrane prepared had a thinner active skin layer (<100 nm) than those of commercial membranes. A permeability of 30.07 L/m 2 /h and a rejection rate of 79.68% for 1,000 mg/L MgSO 4 at 0.2 MPa were obtained. In addiiton, Fe 3+ , Cu 2+ , and Pb 2+ were used to evaluate the heavy metal removal performance of the NF membrane. It was found that as the concentration of heavy metal ions increased to three times of the Standards for Drinking Water Quality (SDWQ) (GB5749-2006), and the rejections to all heavy metal ions were more than 76%. In addition, the NF membrane had a good long-term rejection stability for the heavy metal ions over a 12-month dynamic filtration experiment. The results showed that the newly prepared NF membrane has a good application prospect for domestic water purification.