Effective and sustainable Cs+ remediation via exchangeable sodium-ion sites in graphene oxide fibers

Abstract

A monovalent sodium-functionalized graphene oxide fiber (Na&#8211

GO) structure was synthesized via facile and simple liquid coagulation of a graphene oxide solution. Supported by the stable GO framework, the readily accessible sodium site of this alkali-metal&#8211

carbon heterostructure allows effective removal of Cs+ in aqueous medium with a rapid equilibrium time (∼30 min) and a large adsorption capacity (220 mg g&#8722

1). Na&#8211

GO possesses physical and chemical integrity in a broad pH range (4&#8211

10), and the adsorption behavior is influenced by the hydration radius of the targeting cation, charge effect, π&#8211

M+ interaction, and pH-dependent GO hydrophilicity. In utilizing the chemical potential effect of Na&#8211

GO, a simple regeneration process with NaOH solution selectively releases captured Cs+ and replenishes functional sodium sites within the Na&#8211

GO structure, providing a rechargeable Cs+ remediation functionality. This study demonstrates the successful adaptation of the alkali-metal-induced reversible ion-exchange principle for a versatile GO fiber structure.