Three-dimensional graphene-based macroscopic assemblies as super-absorbents for oils and organic solvents

Abstract

With frequent oil spill incidents and industrial discharge of organic solvents, the development of highly efficient and environment friendly absorbents with both hydrophobic and oleophilic properties have become a top priority. Attributing to exceptionally large specific surface area, intrinsic hydrophobicity, outstanding electrochemical stability and superior mechanical properties, two-dimensional (2D) graphene holds significant promise as advanced absorbents for oil spill response and restoration. However, just as any other carbon allotrope, graphene as a bulk material tends to form irretrievable agglomerates due to strong π-π interactions between the individual graphene sheets. This leads to incompetent utilization of isolated graphene layers for environmental remediation applications. In order to overcome this restacking issue, the integration of 2D graphene macromolecule sheets into 3D macrostructures, and ultimately into a functional system, has materialized as a progressively critical approach in recent years. Consequentially, a wide array of exotic 3D graphene-based macroscopic assemblies (GMAs), such as aerogels, hydrogels, sponges, foams, etc., have been intensively developed during the past five years. Owing to their well-defined and physically interconnected porous networks, these rationally designed macroscopic graphene architectures can support rapid mass transfer in 3D and provide adequate accessible surfaces for molecular absorption, thereby outspreading their application potential. This chapter aims at collating the current state-of-the-art on the development and application of 3D GMAs for ultrafast and recyclable oils and organic solvents absorption. Furthermore, it distinguishes the fundamental knowledge gaps in the domain, and lays out novel strategic research guidelines, all of which will promote further progress in this rapidly evolving cross-disciplinary field of current global interest.