Synthesis of flashed graphene nanocellulose aerogel for microplastic adsorption in aquatic environment

Abstract

Microplastics (MPs), pervasive in oceanic environments, not only negatively impact ecosystems but also pose potential health risks to humans through the food chain. Addressing and controlling water pollution necessitates the development of adsorption materials with high capacity for MPs removal. In this study, a composite aerogel was synthesized using TEMPO-oxidized cellulose nanofibers (TCNF) as the matrix material, flash graphene (FG) as the modifier, and 1,2,3,4-butanetetracarboxylic acid as the crosslinking agent. This aerogel was prepared by freeze-drying and was applied to the adsorption of microplastics for the first time. The chemical properties and physical structure of the resulting TCNF/FG aerogel were characterized. Notably, the specific surface area of the graphene-modified aerogels increased significantly from 212 m² g⁻¹ to 359 m² g⁻¹. These modifications resulted in an impressive adsorption capacity of 103 mg g⁻¹ and a removal rate exceeding 90 % for MPs. The adsorption behavior adhered to pseudo-second-order kinetics, and the effectiveness of the aerogel in capturing MPs was visibly confirmed under a microscope. The primary mechanisms facilitating adsorption included hydrophobic interactions, pore-filling effects, capillary forces, and electrostatic interactions. Therefore, the TCNF/FG aerogel demonstrates a significant potential for effectively removing MPs from aquatic environments.