Facile fabrication of superhydrophobic and superoleophilic glass-fiber fabric for water-in-oil emulsion separation

Superhydrophobic and superoleophilic glass-fiber fabric with high water-in-oil emulsion separation efficiency was prepared by a simple sol-gel process using MTES (triethoxymethylsilane) as precursor. The surface chemical composition, micromorphology, pore size distribution, thermal stability, and the wetting behavior of the glass-fiber fabric were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, capillary flow porometry, thermogravimetric analysis, and water (pH = 1-14)/oil contact angle measurement. The contact angle of the treated fabric at different temperatures was tested in a muffle furnace. The results show that the micromorphology of the glass-fiber fabric almost remains the same after MTES treatment, while the pore size of the treated glass-fiber fabric decreases slightly. Hydrophobic -CH3 groups are grafted onto the fiber surface and MTES copolymers are formed on the junction of fibers of the glass-fiber fabric. The treated glass-fiber fabric shows superhydrophobicity and superoleophilicity and its separation efficiency for emulsified water in the oil can reach 96.80 wt %. Besides, the treated glass-fiber fabric can withstand acid/alkaline, high temperature environments and maintain high separation efficiency after multiple cycle uses.