Recent advancements in hydrophilic-hydrophobic membranes have demonstrated significant potential for enhancing membrane distillation (MD) performance by addressing common obstacles such as wetting and fouling, while improving flux. Despite their potential, hydrophilic-hydrophobic membranes still face challenges such as delamination and the intrusion of the hydrophilic layer into the hydrophobic membrane pores, which contribute to wetting phenomena in MD. This study presents an innovative approach for fabricating polysulfonepolydopamine (PSf-PDA) membranes, incorporating ethanol, 2-propanol, and glycerol as pore-filling materials to prevent hydrophilic layer penetration. To evaluate membrane performance, a direct contact membrane distillation (DCMD) system was operated using a salt solution containing 3.5 wt% NaCl as feed. Membrane characterization (FESEM, FTIR, AFM, and XPS) verified the successful formation of a hydrophilic PDA coating on the hydrophobic PSf membrane, which was further supported by the decrease in water contact angle from 93.3◦ to 46.8◦. This thin PDA layer adhered strongly to the surface, playing a key role in eliminating delamination. Moreover, among the tested membranes, the ethanol-filled PSf-PDA membrane (PSf-Eth-PDA) exhibited the highest performance, reaching a flux of 19.85 kg/m2h and 99.99 % salt rejection, demonstrating the effectiveness of the pore-filling strategy in mitigating wetting. Long-term fouling tests using a saline solution containing 3.5 wt % NaCl and 1 g/L canola oil further demonstrated that the PSf-Eth-PDA membrane maintained stable flux and consistent permeate conductivity over 72 h, confirming its superior antifouling performance. Furthermore, the wetting resistance of the PSf-Eth-PDA membrane was evaluated using sodium dodecyl sulfate (SDS), and the results revealed its remarkable resistance to surfactant-induced wetting. This study emphasizes the role of pore- filling materials in mitigating hydrophilic layer intrusion, advancing the development of high-performance, stable, and fouling-resistant hydrophilic-hydrophobic membranes for membrane distillation.

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