Mg-Fe layered double hydroxide modified montmorillonite as hydrophilic nanofiller in polysulfone- polyvinylpyrrolidone blend ultrafiltration membranes : separation of oil-water mixture

Abstract

Montomorillonite (Mt) and Mg[sbnd]Fe layered double hydroxide modified Montmorillonite (LDH-Mt) were used as nanofillers in polysulfone - Polyvinylpyrrolidone (PSF-PVP) blend ultrafiltration membranes. The nanocomposite UF membranes and virgin PSF-PVP blend membranes were prepared by phase inversion method using water as the gelation medium. The membranes were characterized with respect to their surface hydrophilicity and roughness. Thermal stability, morphology and structure of the membranes were studied. LDH-Mt modified membranes were found to be the most hydrophilic, of best thermally stability and of highest surface roughness when compared with Mt modified and virgin PSF-PVP blend membranes. Asymmetric pore morphology is the characteristics of all the membranes. LDH-Mt modified membranes exhibited pure water flux (PWP) of 592 L m−2 h−1 whereas the values are 335.5 L m−2 h−1 and 208 L m−2 h−1 for Mt modified and virgin PSF-PVP blend membranes respectively indicating comparatively loose surface pore structure of the nanocomposite membranes. The membranes were used for the separation of oil-water mixture. The rejection of transformer oil and motor oil were found to be 87.2% and 95.9% for LDH-Mt modified membranes whereas for virgin PSF-PVP blend membranes the values are 71.8% and 88% respectively.