Novel fabrication of a robust superhydrophobic PU@ZnO@Fe3O4@SA sponge and its application in oil-water separations

Abstract

We report a novel superhydrophobic material based on commercially available polyurethane (PU) sponge with high porosity, low density and good elasticity. The fabrication of a superhydrophobic sponge capable of efficiently separating oil from water was achieved by imitating or mimicking nature’s designs. The original PU sponge was coated with zinc oxide (ZnO), stearic acid (SA) and iron oxide particles (Fe3O4) via a facile and environmentally friendly method. After each treatment, the properties of the modified sponge were characterized, and the changes in wettability were examined. Water contact angle (WCA) measurements confirmed the excellent superhydrophobicity of the material withhigh static WCA of 161° andlow dynamic WCA (sliding WCA of 7° and shedding WCA of 8°). The fabricated sponge showed high efficiency in separation (over 99%) of different oils from water. Additionally, the fabricated PU@ZnO@Fe3O4@SA sponge could be magnetically guided to quickly absorb oil floating on the water surface. Moreover, the fabricated sponge showed excellent stability and reusability in terms of superhydrophobicity and oil absorption capacity. The durable, magnetic and superhydrophobic properties of the fabricated sponge render it applicable to the cleanup of marine oil spills and other oil-water separation issues, with eco-friendly recovery of the oil by simple squeezing process.

Surface Engineering of Ceramic Nanomaterials for Separation of Oil/Water Mixtures

“…Moreover, the sponge is recyclable up to 30 times and suitable for magnetic separation. In some other studies, Fe 3 O 4 nanoparticles have been used in combination with other materials such as zinc oxide, stearic acid (Tran and Lee, 2017 ), silane (Liu et al, 2015 ; Li et al, 2018c ), silica, and fluoropolymer (Wu et al, 2015 ) to modify a PU sponge for oil/water separation.…”

Toward Superhydrophobic/Superoleophilic Materials for Separation of Oil/Water Mixtures and Water-in-Oil Emulsions Using Phase Inversion Methods

“…Recently, superwetting materials that exhibit superhydrophobicity and superoleophilicity have grown into attractive options because of their ability to efficiently separate or selectively adsorb oil (or other hydrophobic organic solvents) from the water [7][8][9][10][11][12][13][14][15]. Liu et al prepared a graphene−melamine sponge through a microwave irradiation method [16].…”

One-step synthesis of a steel-polymer wool for oil-water separation and absorption

“…[2][3][4] For example, in 2010, around 5 million barrels of crude oil spilled into the Gulf of Mexico, killing many marine animals and organisms and costing $600 million. 5,6 Therefore, efficient, effective methods for cleaning up oil and chemical spills in salt and fresh water are desperately needed.…”

“…Researchers have integrated and tested various water-repellent tools with magnetic materials. 5,14,[28][29][30][31][32] To date, three main strategies have been used to synthesize magnetic absorbents. 27 The first method involves depositing a magnetic layer on the porous absorbent's surface.…”