Fabrication of nanocomposite of graphene oxide/bentonite and evaluation its adsorption performances towards methyl orange and methylene blue from aqueous solution

Abstract

Graphene oxide/bentonite (GO/B) nano composite was used as an adsorbent in the elimination of methyl orange and methylene blue dyes from water. Graphene oxide was synthesized via Hummers’ process and doped with bentonite clay. The obtained adsorbent was identified by FTIR, XRD, TGA, TEM and BET surface area. Some parameters such as solution pH, amount of the adsorbent, contact time, the original concentration of the dye and the operating temperature have been studied. The pathway of adsorption was adequately described kinetically and isothermally. The highest capacity of single layer adsorption of MO and MB was estimated to be 18.69 and 19.84 mgg^-1, respectively. ΔG°, ΔH° and ΔS° estimations confirmed the physisorption process with exothermic and spontaneous nature. Moreover, GO/B’s recyclability was promising for using around three runs of adsorption with efficiency above 90 %. Finally, the usage of 50 mg of GO/B to remove MO and MB (50 mg.L^-1) from industrial real specimens showed 95 and 93% recovery and 16.73-74.25% removal efficiency towards different metal ions. The preliminary findings suggested that GO/B could actually remove cationic and anionic dyes from solutions.

GRAPHICAL ABSTRACT

Key words:

• Dyes
• Uptake
• Methyl orange
• Graphene oxide
• Bentonite