Simultaneously Boosting Freshwater Productivity and Antifouling Efficacy of Membrane Distillation Through In Situ Micro‐Bubble Generation

Membrane distillation (MD), combining phase-change purification with membrane separation, is a promising technology for treating industrial hypersaline wastewater with complex organics and residual oxidants (e.g., H₂O₂). However, membrane fouling remains a prominent challenge that limits both productivity and durability. To address this challenge, a superhydrophobic membrane capable of in situ micro-bubble generation is developed at the membrane-liquid interface, effectively mitigating salt accumulation while enhancing vapor transfer. This is achieved by applying a surface coating of γ-MnO₂ and perfluorodecyltrichlorosilane (FDTS) on a commercial polyvinylidene difluoride (PVDF) membrane, which facilitates the decomposition of H₂O₂ in the feed solution. The modified membrane evinced a flux enhancement of up to 35% for desalinating sodium chloride (NaCl) solution under various operating conditions, and its resistance to gypsum (CaSO₄) fouling nearly doubled compared to the unmodified membrane. These improvements are attributed to the synergistic effects of the superhydrophobic property and the dynamic micro-bubbles, which intensified turbulence and acted as nucleation barriers. Compared to recent studies, the developed membrane demonstrated superior productivity, antifouling, and cost-effectiveness across various scenarios. The work provides a scalable and efficient approach for MD applications in hypersaline wastewater treatment.