Explore the Nano World
Wen's Research Group
Wen Zhang, Ph.D., P.E., BCEE
Principal Investigator
Professor
Phone: (973) 596-5520
Fax: (973) 596-5790
Email: wen.zhang@njit.edu
Office Location: Colton Hall 211
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Dr. Wen Zhang’s group in New Jersey Institute of Technology reported a novel conductive Fe3O4/PANI@PTFE membrane which can achieve superior thermal efficiency up to 88% in membrane distillation for seawater desalination. Membrane distillation (MD) is an emerging technology to produce freshwater from saline water. Conventional MD undergoes interfacial temperature polarization and thus may suffer from a reduced thermal efficiency when using the hot saline water as the primary thermal driver. To address this issue, this study coated a conductive Fe3O4/polyaniline (PANI) layer on polytetrafluoroethylene (Fe3O4/PANI@PTFE) membrane by spray coating technique, and achieved local interfacial heating under electromagnetic induction to promote the thermal efficiency of direct-contact MD (DCMD). The key hypothesis confirmed was that incorporating ferromagnetic Fe3O4 nanoparticles in conductive PANI polymer matrix created additional electrically conductive paths, and thus enabled the formation of larger closed loops of eddy currents for higher induction heating efficiency. They demonstrated that the composite Fe3O4/PANI@PTFE membrane doubled the heating efficiency (2.0 oC·s-1) when compared to directly dispersing Fe3O4 nanoparticles onto PTFE without PANI (1.1 oC·s-1). This study also developed an 2D model in COMSOL Multiphysics to simulate the thermal and mass tranfer behaviors. The simulation data matched well with the expreimental results, and determined the thermal efficiency up to 88% as opposed to the reported levels (20~58%) for the conventional DCMD. This study laid additional foundation for induction-heating DCMD by devising new composite membrane materials and new interfacial thermal and mass transfer mechanisms.
Link: https://www.sciencedirect.com/science/article/pii/S2211285521005942
Conductive Fe3O4/PANI@PTFE Membrane for High Thermal Efficiency in Interfacial Induction Heating Membrane Distillation