Adsorption of azo dyes from aqueous solution by the hybrid MOFs/GO

In this work, a hybrid of chromium(III) terephthalate metal organic framework (MIL-101) and graphene oxide (GO) was synthesized and its performance in the removal of azo dyes (Amaranth, Sunset Yellow, and Carmine) from water was evaluated. The adsorption for azo dyes on MIL-101/GO was compared with that of MIL-101, and it was found that the addition of GO enhanced the stability of MIL-101 in water and increased the adsorption capacity. The maximum adsorption capacities of MIL-101/GO were 111.01 mg g⁻¹ for Amaranth, 81.28 mg g⁻¹ for Sunset Yellow, and 77.61 mg g⁻¹ for Carmine. The adsorption isotherms and kinetics were investigated, showing that the adsorption fits the Freundlich isotherm and the pseudo-second-order kinetic model. The recyclability of MIL-101/GO was shown by the regeneration by acetone. The high adsorption capability and excellent reusability make MIL-101/GO a competent adsorbent for the removal dyes from aqueous solution.