Purification of oily seawater/wastewater using superhydrophobic nano-silica coated mesh and sponge

Abstract

Superhydrophobic mesh and sponge were fabricated by a simple and fast dip-coating of silica nanoparticles (SiNP). Hexadecyltrimethoxysilane (HDTMS) was used as a hydrophobic reagent to make the superhydrophobic surface, by being grated onto the SiNP-mesh or sponge. As-made HDTMS-SiNP-mesh showed a water contact angle greater than 150°, meaning the successful creation of a superhydrophobic surface, and a high separation efficiency (99%) of target oils from oily wastewater/seawater even after 20-times recycling test. In kinetic test, the higher the kinematic viscosity of the target oil, the slower the separation rate, but the higher the separation efficiency. Therefore, the present approach of simple and inexpensive fabrication of superhydrophobic HDTMS-SiNP-mesh or sponge could offer promising applications in oil⿿water separation and off-shore oil spills.