Ultra-selective microfiltration SiO2/carbon membranes for emulsified oil-water separation

Microfiltration SiO2/carbon membranes were fabricated by compositing SiO2 microspheres into carbon membrane matrix through facile blending, shaping and pyrolysis. The chemical groups, thermal stability, pore structure, microstructure, morphology, mechanical strength and surface hydrophilicity of the membranes were characterized by the technologies of Fourier-transform infrared spectroscopy, thermogravimetry, bubble pressure method, X-ray diffraction, Scanning/Transmission electron microscope, compressive stress and water/oil contact angle, respectively. The effect of SiO2 amount on the structure and separation performance of the membranes for the purification of oil-water emulsion was investigated. The results showed that the incorporation of SiO2 microspheres improved the surface hydrophilicity/oleophobicity, matrix density, oil removal and anti-fouling ability of carbon membranes. The highest oil removal is up to 99.99%, along with the water permeation flux of 5550 kg·m−2 h−1 MPa−1 for resultant carbon membranes made by the precursor containing 8 wt% SiO2 microspheres. The present work offers an easy approach for preparing microfiltration carbon membranes with highly efficient removal of oil from wastewater.