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MD is a thermally driven process where the vapor pressure gradient over the porous hydrophobic membrane leads to the transport of water vapor. Conventional MD often suffer low thermal efficiency caused by substantial heat loss from hot brine or thermal isolation and temperature polarization. To reduce this heat loss or energy consumption while increasing localized water vapor transport across membrane pores, Zhang’s research has been devising a novel induction responsive membrane since 2018 to enhance the local heating at the membrane-water interface through electromagnetic induction. The localized interfacial heating on membrane surface is achieved under a high-frequency electromagnetic field, which excites the induction responsive membrane and heats up interfacial water molecules. Compared to other similar local heating MD processes (e.g., photo-irradiated membrane heating, Joules heating or electrically heating membrane), the electromagnetic field can more efficiently penetrate the brine solution and membrane module materials and induce localized heating on membrane-water interface, eliminating the heat loss or penetration issues (as encountered by photo irradiation). Thus, the induction assisted MD is a potential game changer that transforms traditional MD to a highly thermal efficient process. This technology could be implemented to the existing tubular membrane module with induction coils to produce alternative induction fields to heat functionalized membranes to separate brine from distilled water. Success of this technology develop may significantly decrease the energy consumption, heat loss and increase water productivity to safeguard water security and to enable cost-efficient and sustainable MD processes for desalination and water purification or on-site water remediation.Under funding support from the U.S. EPA (Award number: SU84014901) and Bureau of Reclamation Department, Award number: R19AC00107), our group focuses on the novel induction-responsive-materials (IRMs) fabrication and membrane integration via coating or other functionalization methods. Moreover, we also investigate the impacts of solution characteristics (e.g., salinity gradient), induction energy intensities and membrane surface properties on the performances of novel MD process. This process will require a fundamental understanding of polarization mechanisms of different magnetic dipoles or electrically conductive materials and magnetically induced eddy currents. Moreover, fabrication methods for IRMs-coated membranes with tunable structures such as IRMs coating density and porosity are crucial, which not only affect the vapor flux transport but also influence the distillation stability. Finally, membrane wetting resistance, fouling resistance and the thermal efficiency are assessed to examine the stability of our proposed MD systems as compared with conventional bulk heating and other localized heating induced MD processes, which are not reported elsewhere in the past.

Electromagnetic induction interfacial heating for high-efficiency membrane distillation

 Wen's Research Group​

Wen Zhang, Ph.D., P.E., BCEE

Principal Investigator

Phone: (973) 596-5520 
Fax: (973) 596-5790
Email: wen.zhang@njit.edu

Office Location: Colton Hall 211

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