Preparation and Performance of Composite Nanofiltration Membrane Modified by Mussel Coating

In this study, relying on different ratios of dopamine (DA) and polyvinylimide (PEI) as mussel coating materials, a new type of mussel-coated modified composite nanofiltration membrane was developed. The effects on membrane flux and retention of the step-by-step and one-step methods were compared. The results showed that the membrane performance was closely related to the different ratios of DA and PEI. When the ratio of DA:PEI was 3:1, the water flux and dye retention rate were the best, and the pollution recovery rate of humic acid reached 86.8%. By optimizing a simple one-step fabrication process, the performance of composite nanofiltration membranes has been greatly improved. Compared with the membrane prepared by the step-by-step method, the pure water flux of the new composite membrane prepared by the one-step method increases by 19.8%, and the retention rate increases by 145.9%. This research will provide a simple, fast, and efficient preparation method for developing new high-performance composite nanofiltration membranes.