Graphene oxide–aluminium oxyhydroxide interaction and its application for the effective adsorption of fluoride

Abstract

A novel aluminium oxy hydroxide [Al–O(OH)] modified graphene oxide was prepared by a chemical precipitation method wherein Al³⁺ ions could interact effectively with the different functional groups of graphene oxide (GO). The prepared (GO–Al–O(OH) adsorbent was tested for the effective defluoridation of water. The Al³⁺ modified graphene oxide adsorbent was characterized using FT-IR, FT-Raman, SEM-EDS, XRD and XPS studies. The thermodynamically feasible adsorption is supported by the pseudo second order kinetics and a high Langmuir maximum adsorption capacity (51.42 mg g⁻¹) for the GO–Al–O(OH) adsorbent. Furthermore, we could treat 2.0 L of 5.0 mg L⁻¹ fluoride ion solution to bring the level within the permissible limits and the regeneration of the adsorbent was done using ammonium hydroxide.