Pressurizing\nDistillate Membrane Distillation Assisted\nby Impedance-Based Liquid Entry Pressure Measurement for Effective\nWetting Mitigation

Membrane wetting is a prominent challenge in the practical\napplications\nof membrane distillation (MD). In this study, we hypothesize that\nincreasing the hydraulic pressure on the distillate side (<i>P</i><sub>d</sub>) can mitigate membrane wetting, an operation\nmode we refer to as pressurizing distillate membrane distillation\n(PDMD). To implement PDMD, an accurate measurement of the liquid entry\npressure (LEP) of the membrane with the feed solution is essential.\nHowever, the conventional LEP measurement method struggles with solutions\ncontaining amphiphilic agents. Herein, we develop an impedance-based\nLEP measurement method and validate it by measuring the LEPs of a\ncommercial poly(tetrafluoroethylene) (PTFE) membrane with ethanol–water\nmixtures. Further, we demonstrate that this method can accurately\nmeasure the LEPs of the PTFE membrane with solutions containing sodium\ndodecyl sulfate (i.e., a representative amphiphilic agent) by capturing\nthe subtle changes of the feed solutions within the membrane. Additionally,\nwe show that PDMD can effectively mitigate membrane wetting induced\nby various wetting agents, as the elevated <i>P</i><sub>d</sub> results in a transmembrane hydraulic pressure lower than\nthe LEP of the membrane. Overall, our study provides an effective\nwetting mitigation approach that can be easily applied in practical\nMD and membrane contactor applications.