In situ engineering of an ultrathin polyamphoteric layer on polyketone-based thin film composite forward osmosis membrane for comprehensive anti-fouling performance

Thin film composite (TFC) membranes easily suffer from fouling induced by oil and other pollutants during forward osmosis (FO) due to the relatively hydrophobic chemistry and rough structure of polyamide (PA). To achieve comprehensive anti-fouling properties, poly(2-methacryloyloxyethyl phosphorylcholine-co-2-aminoethyl methacrylate hydrochloride) (MPC-co-AEMA) was immobilized on top of a polyketone (PK)-based TFC membrane following a single-step simultaneous deposition with dopamine. The adhesive properties of polydopamine (PDA), as well as the covalent interactions between PDA and MPC-co-AEMA, ensured the firm immobilization of the MPC-co-AEMA on PA layer. As a result of the simultaneous deposition of PDA and MPC-co-AEMA, a high-performance and superhydrophilic and underwater superoleophobic TFC membrane was engineered. In addition, the outstanding water adsorption capacity of the polyamphoteric layer resulted in better protein adhesion mitigation. FO operation using various foulants also demonstrated a high fouling resistance of the PK-TFC-PDA/MPC membrane, especially during the treatment of wastewater emulsion containing high concentration of oil and bovine serum albumin (BSA). In summary, the findings in this study could provide insights into the preparation of anti-fouling membranes for wastewater purification using FO.