Micro–nano structural engineering of filter paper surface for high selective oil–water separation

Cellulose-based lotus-leaf-like filter paper for selective separation of oil/water was prepared. Experimentally, cellulose nanofibril aerogel microspheres prepared by ultrasonic atomization method were coated on commercial filter papers to form unique “micro–nano” structured surface. By controlling both the morphology and chemistry of the surface, the papers could be either under-water superoleophobic or under-oil superhydrophobic. It was found that the filter papers could be engineered to effectively filter only oil or only water from their mixtures.