Concurrent enhancement of structure stability and adsorption capacity of freeze-dried graphene oxide aerogels via the removal of oxidation debris nanoparticles on nanosheets

Abstract

The stability and adsorption capacity of three-dimensional aerogels (GAs) of graphene oxide (GO) are two important factors that determine its environmental applications. However, enhancement of stability by reduction or crosslinking methods results in the decrease of active sites, thereby impairing the adsorption performance of GAs. Herein, the structure stability and adsorption capacity of GAs were concurrently enhanced by the removal of oxidation debris (OD) nanoparticles from the GO nanosheets. The GA materials of 3D GO and 3D bwGO were fabricated by a freeze-drying approach using GO and base-washed GO (bwGO) as precursors, respectively. The micro/nanostructures in bwGO nanosheets after the removal of OD were created and incorporated into the 3D bwGO aerogel. The structure of 3D bwGO maintained an integrated structure, while the structure of 3D GO collapsed upon hydraulic vibration. The enhanced chemical interaction and physical binding facilitated the adsorption of 3D bwGO for hydrophobic phthalic esters. The increase of the sp² region and carboxyl content, the decrease in the adhered water molecules, and the created wrinkles and folds contributed to the stability and adsorption virtues of 3D bwGO. This study provides insights into the facile fabrication of stable GA with a high adsorption capacity by removing OD nanoparticles from GO nanosheets for environmental applications.