Impact of nanoclays on polyvinylidene fluoride mixed matrix membranes for the efficient treatment of oily wastewater

Abstract

Background: Membrane technology demonstrates a sustainable methodology for water reclamation from oily wastewater but is prone to fouling during longer filtration runs. In this study, fouling-resistant polyvinylidene fluoride (PVDF) mixed matrix membranes (MMMs) containing nanoclays, such as halloysite (HT) and montmorillonite (MMT), were fabricated for the effective treatment of oily wastewater. Methods: The phase inversion technique was followed for the fabrication of HT-PVDF and MMT-PVDF MMMs. Physiochemical characterization and filtration experiments were studied to evaluate the influence of nanoclays on PVDF membrane performance. Results: Fourier transform infrared spectroscopy (FTIR) and morphology analyses indicated that both nanoclays were layered and structured with abundant hydrophilic functional groups. The dispersions of HT and MMT were confirmed by surface morphology and topography analysis of PVDF MMMs. The hydrophilicity property was improved in HT-PVDF and MMT-PVDF MMMs, which was evident in the contact angle analysis. Among the membranes, MMT-PVDF MMMs held a higher water permeability of 2.59 x10-8 m/s.kPa. For oil-water filtration, HT-PVDF and MMT-PVDF MMMs displayed higher normalized flux with a maximum rejection of more than 95%. Conclusion: Overall, MMT would be a cost-effective nanofiller for developing antifouling PVDF MMMs against oil-water filtration.