MOF-incorporated PVDF adsorptive membrane for dye removal from aqueous solution

This work investigated the performance of Polyvinylidene fluoride-based membranes for the removal of Methylene blue (MB). Previously synthesized MIL-53(Fe)-(COOH)₂ nanotubes, a type of metal organic framework (MOF), were incorporated into the PVDF matrix. Accordingly, adsorptive membranes were prepared with varying dosage of MIL-53(Fe)-(COOH)₂ nanotubes (0-0.6 wt%). The as-prepared PVDF-based membranes were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle measurement, X-ray powder diffraction (XRD), and attenuated total reflectance infrared (ATR-IR) spectroscopy. The adsorption capabilities of the as-prepared membranes were evaluated by assessing their efficiency in removing MB and their pure water permeability (PWP). The maximum removal efficiency of 99% was obtained with PWP of approximately 81 (L.m^-2.h^-1.bar^-1) or (LMH) for a membrane containing 0.4 wt% of MOF. Furthermore, the reusability of the optimal membrane was approved via subsequent adsorption and regeneration cycles over a period of 36 h. Finally, the adsorption mechanism was investigated using curve fitting on the Langmuir and Freundlich isotherms. Based on these findings, it can be concluded that the PVDF/MIL-53(Fe)-(COOH)₂ membrane is a promising candidate for dye removal applications.