Enhanced naproxen adsorption by a novel β-cyclodextrin immobilized the three-dimensional macrostructure of reduced graphene oxide and multiwall carbon nanotubes

Abstract

In this study, a novel β-cyclodextrin immobilized the three-dimensional macrostructure of reduced graphene oxide and multiwall carbon nanotubes (β-CD/rGO-MWCNTs) was synthesized with hydrothermal reduction and chemical crosslinking, adopting as an effective adsorbent for naproxen removal in aquatic environments. With a larger specific surface area (SSA) and excellent porous structure, β-CD/rGO-MWCNTs ensured a large internal space, which was conducive to the preservation of adsorption sites and naproxen diffusion. The maximum naproxen adsorption capacity (qm) value of β-CD/rGO-MWCNTs stood at 132.09 mg g−1 at room temperature, higher than that of most of the commonly used naproxen adsorbents. Such immense adsorption was attributed to hydrophobic interaction, electrostatic interaction, π/n-π interaction and hydrogen bonding. The naproxen adsorption kinetics and isotherm on the adsorbents match the pseudo-second-order kinetics model and the Freundlich model better. The thermodynamic parameters certified the naproxen adsorption on β-CD/rGO-MWCNTs as a favorable, thermodynamically feasible and exothermic process. The stable three-dimensional (3D) structure endowed the adsorbent with an excellent regeneration performance and practical application potential.