Assessing the desalination performance of MIL-68(In) MOF-filled PVDF membranes in vacuum membrane distillation

Our work investigates the feasibility of MIL-68 (In), a metal-organic framework (MOF), to enhance the desalination performance of hydrophobic PVDF membranes in vacuum membrane distillation (VMD). Using non-solvent induced phase separation, we successfully synthesized highly stable, porous, and selective MIL-68 (In) integrated PVDF membranes. The effect of varying MOF loadings (0.25, 0.5, 1.0, and 2.0 wt%) on total permeate flux and salt rejection was assessed at various feed temperatures. Additionally, the developed membranes have been characterized using water contact angle measurements, scanning electron microscopy (SEM), mechanical testing, x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and pore size analysis, revealing significant enhancements in desalination performance and membrane properties. The membrane presenting the highest MIL-68 (In) loading (2wt%) revealed an exponential increase in permeate flux while maintaining the high salt rejection rates (over 99.7%) with stable VMD performance of 72 h. The experimental outcomes reveal that MIL-68 (In) modified PVDF membranes could be a potential hybrid material for membrane fabrication for VMD desalination applications.