Carboxymethyl cellulose/polyethersulfone thin-film composite membranes for low-pressure desalination

Herein, we report the fabrication of carboxymethyl cellulose (CMC)/polyethersulfone (PES) thin-film composite nanofiltration membranes using a dip-coating method with glutaraldehyde (GA) as the crosslinking agent. The effects of crosslinking degree and the dip-coating parameters, including CMC concentration and dipping time, on the performance and morphology of the fabricated membranes were investigated. The properties of the prepared membranes were analyzed by ATR-FTIR, AFM, FE-SEM, and water contact angle analysis. The optimized membrane containing 0.2 wt% CMC, crosslinking degree of 20% by the dipping time of 10 min represented a rejection efficiency of 91.90%, 68.63%, and 45.90% towards the Na₂SO₄, MgSO₄, and NaCl solutions (100 mg/L), respectively. The pure water flux of the optimal membrane was 47.90 ± 1.77 L/m² h under a low transmembrane pressure of 0.4 MPa. The flux recovery ratio of the nanofiltration membrane was 63% higher than the PES support membrane, indicating an improvement in fouling resistance.