Superwetting Polymeric Three Dimensional (3D) Porous Materials for Oil/Water Separation: A Review

Abstract

Oil spills and the emission of oily wastewater have triggered serious water pollution and environment problems. Effectively separating oil and water is a world-wide challenge and extensive efforts have been made to solve this issue. Interfacial super-wetting separation materials e.g., sponge, foams, and aerogels with high porosity tunable pore structures, are regarded as effective media to selectively remove oil and water. This review article reports the latest progress of polymeric three dimensional porous materials (3D-PMs) with super wettability to separate oil/water mixtures. The theories on developing super-wetting porous surfaces and the effects of wettability on oil/water separation have been discussed. The typical 3D porous structures (e.g., sponge, foam, and aerogel), commonly used polymers, and the most reported techniques involved in developing desired porous networks have been reviewed. The performances of 3D-PMs such as oil/water separation efficiency, elasticity, and mechanical stability are discussed. Additionally, the current challenges in the fabrication and long-term operation of super-wetting 3D-PMs in oil/water separation have also been introduced.

Complex Aerogels Generated from Nano-Polysaccharides and Its Derivatives for Oil–Water Separation

“…They are consisted of both crystalline and amorphous domains, though the amorphous region can be removed by using a controlled acid or enzymatic hydrolysis, or an oxidation reaction by using 2, 2, 6, 6-tetramethylpiperidine-1-oxyl (TEMPO) or nitric acid/sodium nitrite [20,21,22,23,24]. The released crystalline segments are usually referred to as nanocrystals, nanowhiskers, or nanofibers, and have been demonstrated to have various potential applications by many researchers [25,26,27,28], including their use in the preparation of aerogels for oil–water separation [29,30,31,32].…”

Non-Fluorinated, Sustainable, and Durable Superhydrophobic Microarrayed Surface for Water-Harvesting

“…As described previously, the surface is formed by vertically aligned microarrays with a non-linear cone shape that are combined with flower-like structures leading to a hierarchical structure through the whole surface. Water droplet dynamics is governed by Laplace pressure [60]. In a non-linear cone shape, average Laplace pressure will decrease inside the water droplet, which leads to increase its pressure gradient from the tip to the base of the non-linear cone and the water droplet will move away from the tip on a conical surface [61][62][63].…”

Facile Fabrication of Superhydrophobic Cross-Linked Nanocellulose Aerogels for Oil–Water Separation

“…Inspired by lotus leaf, the superhydrophobic surfaces have received great attention in oil spill treatment [ 13 , 14 , 15 ]. Many reports have proved that appropriate rough morphology and low surface energy are indispensable to fabricate superhydrophobic materials [ 16 , 17 , 18 ]. A bottom-up assembly process is commonly used for the preparation of superhydrophobic aerogels [ 19 , 20 ].…”