Regulating the structure of cellulose-based ultrafiltration membrane to improve its performance for water purification

Cellulose and its derivatives have received much attention as green raw materials to prepare ultrafiltration membranes. However, the inferior performance (low rejection, poor anti-fouling etc.) hinders their development. To improve the preparation of cellulose based ultrafiltration membrane and its performance, in this study, we developed a facile strategy to fabricate cellulose acetate ultrafiltration membranes by adding methyl acetate (MAC, as a co-solvent) to N, N-dimethylacetamide (DMAc). The results show that the pore morphologies of the membrane can be regulated by adjusting the DMAc to MAC ratio. Under optimal conditions, the pure water flux can reach 188.0 L/m2h, with the BSA rejection ratio of 95.2 %, which is about 20 % higher than the control. Furthermore, the anti-fouling and long-term stability of ultrafiltration membranes have improved significantly. The above results support the conclusion that using a mixed solvent by adding MAC to DMAc is effective for tuning the pore structure of cellulose-based ultrafiltration membrane, hence, improving its performance for water purification.