Synthesis and optimization of low-cost metal-organic frameworks from melamine and bauxite for efficient removal of bromocresol green from water using response surface methodology

Sustainable chemistry is an important subject in the research area, so the metal-organic framework (MOF) was synthesized through the solvothermal method with bauxite as a natural source of metal and melamine as a ligand. The characters of as-synthesized MOF were investigated by FTIR, XRD, FESEM, EDS, TEM, and TGA techniques. The application of this material was studied for the removal of bromocresol green (BCG) as organic dye through the Response Surface Methodology (RSM) method by I-optimal and quadratic model. The study of adsorption process determined the impact of pH and adsorbent dose on the yield of removal. The best yield was obtained at acidic pH and 0.024 g adsorbent dose, 18.8 ppm concentration, 90 min, and 15 °C. Based on the finding, Langmuir isotherm and pseudo-second-order model were corresponded to remove BCG, and the thermodynamic study revealed spontaneous and endothermic adsorption process, which the adsorbent can be recycled and reused at four times. This research can be introduced new insight into achieving green chemistry by using natural and low-cost starting materials.