Oil-Water Separation by ZnO-Based Superhydrophobic PU Sponges

Abstract

Continuous oil–water separation is not only an important topic for scientific research but also for practical applications to clean oil from industrial oily wastewater and oil-spill pollution. In this work, polyurethane sponges are coated by ZnO using dip coating technique. ZnO-coated sponges are modified by stearic acid to achieve superhydrophobicity. The ZnO-coated sponges exhibit water contact angle ≈165° and oil contact angle ≈0°. The prepared superhydrophobic sponge is sustained in oil–water separation and in separation of oil–hot water mixture. Also the wetting properties of the sponge are stable in mechanical test like cutting and twisting. Stearic acid modified ZnO-coated sponge holds good promise for oil-spill cleanup as well as oil/water separation from harsh environments.