Fabrication of high performance polyamide reverse osmosis membrane from monomer 4-morpholino-m-phenylenediamine and tailoring with zwitterions

It is well known that the water flux and antifouling performance of polyamide (PA) membrane are strongly associated with their surface characters, especially for surface hydrophilicity, roughness, and charge. In this study, a zwitterionic surface TFC reverse osmosis (RO) membrane was fabricated by small molecule 3-bromo-propionic (3-BPA) modification on the pristine membrane that fabricated through interfacial polymerization (IP) technique using a new aqueous monomer 4-morpholinobenzene-1,3-diamine (MpMPD) and trimesoyl chloride (TMC). The as-fabricated RO membranes were well analyzed by various techniques, that the zwitterionic MpMPD-PA membrane surface exhibited greatly enhanced hydrophilicity with water contact angle of 28.1 degrees and surface roughness as low as 26.0 nm. The water permeability of membrane MpMPD-PA reached 1.65 L m(-2) h(-1) bar(-1), which exhibited similar to 24% increase compared to our lab-made MPD membrane, meanwhile kept a high NaCl rejection of 97.8%. In addition, the dynamic fouling experiments illustrated that the zwitterionic surface RO membrane possess excellent fouling resistance to protein BSA, polysaccharides SA, and surfactant SDS. Therefore, this work provide a simple and convenient way to fabricate novel zwitterionic surface RO membrane with high performance from the molecular level design.