Fabrication of High-Performance Nanofiltration Membrane Using Polydopamine and Carbon Nitride as the Interlayer

In order to recover lithium from brine with a high Mg2+/Li+ ratio, positively charged nanofiltration (NF) membrane was prepared by depositing polydopamine (PDA)-coated graphitic carbon nitride (g-C3N4) as the interlayer (PDA-g-C3N4) and interfacial polymerization (IP) of polyethyleneimine (PEI) trimesoyl chloride (TMC) carried out. Under optimal conditions, water contact angle composite is only 55.5° isoelectric point (IEP) 6.01. The final NF (M5) exhibits permeance (10.19 L·m?2·h?1·bar?1) rejection Mg2+ (98.20%) but low Li+ (13.33%). separation factor (SF) up 48.08, ratio permeate 0.036 in simulated brine. conclusion, M5 shows good performance for salt lake (SF = 12.79 1.43) fouling resistance. Therefore, PDA-g-C3N4 has potential be used recovery