Reduced graphene oxide-based hydrogels for the efficient capture of dye pollutants from aqueous solutions

Three dimensional (3D) reduced graphene oxide (RGO)-based hydrogels were synthesized by the reduction of graphene oxide using sodium ascorbate. During gelation, mono-, bi-, and trilayer graphene nanosheets self-assemble into a well-defined and interconnected 3D porous network through strong van der Waals and π–π interactions. The 3D RGO-based hydrogels showed a large surface area, and a uniform pore size distribution. The application of the 3D mesoporous material as an adsorbent for the removal of the organic dyes, methylene blue (MB) and rhodamine B (RhB), from aqueous solutions was investigated. The 3D RGO-based hydrogels showed excellent removal capabilities for MB (∼100%) and RhB (∼97%) due to adsorption through strong π–π stacking and anion–cation interactions. Toxicity tests show that the aqueous solutions purified by 3D RGO-based hydrogels are comparable to control experiments conducted using distilled water.