Adsorptive removal of malachite green dye using ferrocene incorporated iron-based metal–organic framework: a sustainable approach to wastewater treatment

Abstract

In this work, a mesoporous metal–organic framework, namely FeFc MOF, has been prepared using the co-precipitation method. An aqueous-based experiment was used as an adsorbent for the removal of malachite green (MG) dye from water. The synthesized material was characterized in detail, while the adsorption of the dyes in aqueous medium was monitored by UV–visible spectroscopy. Adsorption equilibrium was attained in 210 min at pH 7 and 298 K. The adsorption was favorable at higher concentrations and increased with an increase in contact time. The removal of dye was maximum at high temperatures and at pH 10. It was most likely due to the formation of advantageous associations between the dye and MOF. The adsorption process was governed by the Freundlich adsorption isotherm and pseudo-second-order kinetics, with a K₂ of 8.5 × 10⁻³ for adsorption of malachite green (MG) dye on FeFc MOF. The thermodynamic study suggests that the process is spontaneous and endothermic. Column data show the FeFc MOF shows practical utility with a long run for large amounts of dye and can be reused up to four cycles.