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.

Nanostructure-Based Oil–Water Separation: Mechanism and Status

“…Therefore, they could be regarded as a kind of self-swelling oil-absorbing material. These porous materials can not only directly absorb oil but also absorb oil floating on the water surface or oil in an oil-water mixture [58]. As one of the major environmental problems, marine oil spilling accidents seriously harm marine ecosystems and coastal environments, resulting in a severe loss of fuel resources [59].…”

Development of self-cleaning superhydrophobic cotton fabric through silica/PDMS composite coating

“…Hence, the rolling water droplets can easily collect dust particles on the way and clean surface itself, this performance is recognized as self-cleaning or lotus effect [2]. Till a date, the superhydrophobic surfaces have been used for self-cleaning [3], oil-water separation [4], anti-freeze [5], and anti-corrosion [6] applications. Many efforts have been made to fabricate superhydrophobic coatings using various fabrication techniques such as phase separation [7], spray coating [8], drop-casting [9], dip coating [10,11] and so on [12,13].…”