Modified ceramic membranes for low fouling separation of water-in-oil emulsions

Growing environmental concerns have fueled the need for efficient separation of oil–water mixtures. Membranes that separate oil–water mixture based on contrasting wetting properties have recently received significant attention. Here, hydrophobic and oleophilic ceramic membranes have been successfully prepared for the application of water-in-oil emulsion separation. The membranes were fabricated by modification the ZrO₂ membrane with hexadecyltrimethoxysilane (HDTMS). SEM, EDS, and pore size measurements depict that HDTMS has been grafted onto the ZrO₂ membrane surface without changing the membrane morphology and pore structure. Contact angle measurements confirm that HDTMS modification improves the membrane hydrophobicity and oleophilicity. The modified membrane was thermally stable to 220 °C, and had good chemical stability in a series of organic solvents, even under high-speed scouring. The antifouling performance of the modified membrane was assessed via the filtration of water-in-oil emulsions. The modified membranes showed higher oil flux and higher water rejection compared with the unmodified membranes. The modified membrane can separate all the water droplets from the water-in-oil emulsions. The hydrophobicity of the grafted HDTMS chains was considered to be responsible for reducing the water droplet adsorption on the membrane surface.