Fluorinated silica–modified anti–oil-fouling omniphobic F-SiO2@PES robustmembrane for multiple foulants feed in membrane distillation

Abstract

Direct-contact membrane distillation (DCMD) can be eminent solution for oily wastewater treatment if the membrane provided is slippery and tolerant to low surface tension complex solutions. This study describes preparation of an anti-oil-fouling omniphobic polyethersulfone membrane using fluorinated silica nanoparticles (FeSiO2@PES) combined with perfluorodecyl triethoxysilane and polydimethylsiloxane for application against oil-In-water (o/w) emulsions. Feed solutions consist of different concentrations of oil (hexadecane), different charge surfactants (anionic sodium dodecyl benzenesulfonate, non-ionic Tween 20, and cationic hexadecyltrimethylammonium bromide, and salt (NaCl). The hierarchical re-entrant micro structured surface of the omniphobic FeSiO2@PES membrane and functional groups are confirmed by atomic force microscopy, scanning electron microscopy, and Fourier-transform infrared spectroscopy. The antieoil-fouling and antiewetting performance of omniphobic FeSiO2@PES membranes are investigated using contact-angle, sliding angles, DCMD tests with multiple foulants of surfactants. Omniphobic FeSiO2@PES membrane exhibited effective anti-oil-fouling and antiewetting performance against emulsions as no severe fouling and a conductivity rises were evident regardless of surfactant charge and the concentration of components. Flux reduction and rejection rates for the omniphobic FeSiO2@PES membranes are in a range of 5-15% (only) and >99%, respectively, for various combinations of feed solution components.