Development of iron-based metal-organic frameworks for the efficient removal of industrial dye: Effect of ligands on morphological and adsorption parameters

Abstract

Recently, the utilization of metal-organic frameworks (MOFs) enhanced the significance of the adsorptive removal of pollutants by several folds. To explore the unmatched potentials of MOFs, MIL-100 & MIL-101 (iron-based MOFs) have been fabricated via a solvothermal process for Orange G dye removal (adsorption-based) from the aqueous system. The adsorption results show that MIL-100 has superior adsorption capacity (357.3 mg/g) in comparison to MIL-101 (206.9 mg/g) via pseudo-second-order kinetics. Moreover, both the adsorbents displayed their effectiveness for the removal of Orange G dye under extreme testing conditions (e.g., varying pH and high salt strength). The interactions between the target dye with the adsorbents have been inferred using three different adsorption isotherm models. Fascinatingly, as per isotherm models, significantly higher q_max values of 540.5 and 321.5 mg/g were achieved using MIL-100 and MIL-101, respectively. The current study revealed that the ligand type is crucial in deciding the MOF properties and their adsorption capacities.