Synthesis of a metal-organic framework with red mud for organic pollutant adsorption using response surface methodology for sustainable chemistry

This study revealed the synthesis of a novel metal-organic framework (MOF) through the reaction between red mud as an industrial waste material, and trimesic acid (TCA) for the adsorption of methyl orange (MO) through Response Surface Methodology (RSM) from aqueous solutions. The synthesis process utilized red mud as a sustainable source of metal ions and TCA as the organic linker to obtain Red Mud-Trimesic Acid MOF (RM/TCA-MOF) under hydrothermal conditions. The synthesized MOF was characterized using various techniques such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Energy dispersive X-ray (EDX), Brunauer-Emmett-Teller (BET) surface area analysis, Transmission electron microscopy (TEM), and Thermogravimetric Analysis (TGA). The as-synthesized MOF was applied to remove methyl orange (MO) as an anionic dye. Response Surface Methodology (RSM) was used to optimize adsorption parameters, including pH, adsorbent dosage, contact time, temperature, and initial dye concentration. Further, the optimum conditions for maximum adsorption efficiency were evaluated at pH = 2.33, 0.07 g RM/TCA dose, 6 ppm of MO concentration, 61 min, and 26 °C using the Quadratic model. Based on the results, RM/TCA-MOF can be adsorbed MO by active functional groups derived from the red mud and TCA. The study of adsorption isotherms and kinetics studies shows the Langmuir isotherm and pseudo-second-order kinetics, respectively. This study considers the potential industrial waste and green chemistry principles to develop effective compounds for environmental subjects.