MagMD · Magneto-responsive hydrophobic membrane and membrane distillation: insight into the real-time fouling and wetting mitigation mechanism

Water scarcity and pollution are key global threats, and to generate water from seawater or brackish water and the effective reuse of industrial wastewater are essential to achieve the sustainable development goals and carbon neutrality. Membrane distillation (MD) is inherently a problem-solver for high salinity seawater and wastewater, and is recognized as an effective strategy for zero liquid discharge (ZLD). However, membrane fouling and wetting are two key issues, which impede its industrial application. MagMD is an application-oriented project, intending to introduce the “magnetic magic” into hydrophobic membrane with a “material- mechanism- application” route, targeting at the commercial application of MD. Three magneto-responsive membranes (magMEMs) will be prepared by incorporating Fe3O4, in order to explore the effects of surface & bulk nano-heating, nano-mixing, and hydrophilic modification on MD. Then, the molecular fouling mechanisms will be demonstrated by combining membrane autopsy, extended-Derjaguin-Landau-Verwey-Overbeek theory (XDLVO), and density functional theory (DFT). The wetting mechanism and the effect of surface & bulk nano-heating on wetting mitigation will also be revealed by water evaporation rate test and long-term MD process. The magMEMs are used for RO concentrate treatment, by applying an alternating magnetic field (AMF) for real-time fouling and wetting mitigation. The long-term performance and the membrane fouling distribution and mechanism will be studied to evaluate the potential of industrial applications. MagMD will uncover the “magic” of magnetism and advance the membrane fouling & wetting mitigation theories and methods. The results will pave a new way for smart gating membrane, and offer a new solution for fouling and wetting control in MD. It will contribute to both state-of-the-art theoretical advancements and practical implementations of MD, bring significant environmental, economic, and social benefits.