Removal of antimony(III) from aqueous solution by graphene as an adsorbent

In this work, graphene is suggested as an adsorbent to remove Sb(III) from aqueous solution. Graphene was obtained using a modified Hummers’ method and then investigated its ability to remove Sb(III) in solutions. The graphene was characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area and Zeta potential measurement. The adsorption of Sb(III) onto graphene was carried out under various conditions, that is, the initial concentration, the contact time, the solution pH and temperature. The adsorption data were successfully modeled using Langmuir (R = 0.977) and Freundlich (R = 0.985) isotherms. The kinetics of adsorption was also investigated. The experimental data showed a good compliance with the pseudo-second-order kinetic model, indicating the process was controlled by the chemical process. The calculated adsorption capacity qe (8.056 mg/g) is in accordance with the experimental data (7.463 mg/g). In addition, graphene showed excellent reusability with 0.1 mol/L of EDTA solution as desorbing agent and could be used as a potential adsorbent in wastewater treatment.

► Graphene exhibited better adsorption capacity for antimony(III) from aqueous solutions.
► The adsorption kinetic shows good compliance with the pseudo-second-order kinetic model.
► Graphene showed excellent reusability during five cycles adsorption–desorption.