Abstract
Graphene aerogels (GAs) are three-dimensional (3D) graphene sponges with unique wettability and have demonstrated the potential for reducing contamination from oil spills and chemical accidents. Herein, we report new polyurethane (PU) sponge-reinforced GAs with low surface energy, high sorption capacity and excellent recyclability for use as efficient oil sorbents. Spongy graphene aerogels (SGAs) with a hierarchical porous morphology were produced by simply freeze-casting reduced graphene oxide (rGO) to form compacted macroscale sponges. This novel micro-structure benefits from the advantages of embedded graphene and presents reversible large-strain deformation (90%), high compressive strength (63 kpa) and viscoelastic stability. These superior properties, in addition to super-hydrophobicity, endow the aerogels with excellent recyclability without deteriorating the oil absorption performance. Furthermore, SGA has selective and high-volume absorbability (>100%) and can efficiently separate oil from water under continuous pumping action. The excellent absorption performance and robust mechanical properties make this graphene material promising for the large-scale recovery of spilled oil.
Highlights
Fossil fuels such as crude oil are the bedrock of modern civilization and are still in very high demand
After the sponge-reinforced composite was exposed to a combined freezing and additional reduction treatment, the reduced graphene oxide (rGO) sheets formed a micro-porous network among the void spaces of the polyurethane sponges (PUS) cell array, and all the networks along the macrocellular skeleton formed an hierarchical porous nanocompostie
From Fig. (1d), we can see that spongy graphene aerogels (SGAs) exhibits a hierarchical skeleton similar to that of pure CGA, indicating that rGO is mainly located within the network instead of coated on the sponge skeleton
Summary
Fossil fuels such as crude oil are the bedrock of modern civilization and are still in very high demand. A variety of sorbent materials with different porosities and surface chemistries, such as natural organic materials, inorganic mineral products, synthetic membranes, microporous polymeric materials and carbon-based nanomaterials, have been used for oil recovery Due to their high accessible pore volume and unique wettability as well as their modification possibilities, microporous polymers and advanced carbon nano-materials have obvious advantages over other absorbents. Dip-coating is a facile one-step process, and microporous polymers coated with the graphene “skins” have recently attracted intense research interest for oil-water separation recently These graphene-coated materials which have unique wettability have been synthesized using commercially available foams such as melamine[20,21], polydimethylsiloxane (PDMS)[22] and polyurethane sponges (PUS)[23,24]. We investigated effect of different concentrations of the graphene oxide (GO) hydrogel precursor on surface wettability and hydrophobic mechanism
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