Continuous and efficient oil/water separation by special wettability granular filter media

To improve the separation efficiency of the oil/water mixture and simplify the separation process, a superhydrophilic/underwater superoleophobic quartz sand filter media (PR@QS) was prepared by coating potato residue onto the quartz sand surface, and an oil/water mixture separator containing two horizontally placed filter columns and one inlet chamber was proposed. One filter column was filled with the PR@QS, and the other column was filled with the superhydrophobic/superoleophilic quartz sand filter media. The experimental results showed that the separation efficiencies of five kinds of oil/water mixtures (petroleum ether, engine oil, diesel oil, cyclohexane, and methylene chloride) were up to 99.4%. Except for engine oil, the hydraulic conductivities of the other four oils and water are all greater than 3.5 m/h. When the filter layer is invaded by the lyophobic liquid, its filtration performance can be restored by backwashing. In summary, the separator can separate oil/water mixtures continuously and efficiently without filter contamination. Therefore, it has a broad prospect for practical application.