Superoleophilic and superhydrophobic carbon membranes for high quantity and quality separation of trace water-in-oil emulsions

Oil purification is an important issue, with its growing commercial demand. In this work, a superoleophilic and superhydrophobic carbon membrane was prepared, and its potential for trace water-in-oil (w/o) separation was evaluated. The carbon membrane was prepared by a spin coating method, with optimization of variables such as spin speed and coating times, and then pyrolyzed at a high temperature under vacuum. Using a capillary flow porometer, the dominated pore-throat size distribution of the carbon membrane was shown to be ranged from 0.5 to 2.5 µm. Furthermore, the separation performance and fouling mechanism were analyzed using several cake filtration models. In the case of low TMP (0.110 bar), steady flux rates with clean membranes were 1203 L/m²/h, which is much higher than in microfiltration systems, and the water content of the permeate flux could be reduced to 0.0306%. The model correlations also indicated that the specific cake resistance obtained in this case was considerably lower than 4.8 min/L².