Iron metal-organic frameworks: Synthesis, characterization and application in phenol degradation in wastewater

This study reports the synthesis of two iron(III)-based metal-organic frameworks, Fe-MOFs (1) and (2), characterized through various techniques and their catalytic application in phenol degradation. The hydrothermal synthesis involved ferric nitrate nonahydrate, glutaric acid, and phloroglucinol for Fe-MOF (1) and ferric nitrate nonahydrate, glutaric acid and thiocynuric acid for Fe-MOF (2). Characterization of the Fe-MOFs was accomplished via infrared (IR) spectroscopy, field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX) analysis, powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA), which confirmed the synthesis. This study highlighted the significant catalytic activity of these Fe-MOFs (1) and (2) for phenol degradation studies in the presence of hydrogen peroxides. The optimal phenol degradation occurred at pH values ranging from 4-5, temperatures ranging from 30-40 degrees C, 0.01-0.02 g/L of the Fe-MOFs and 10 mmol of hydrogen peroxide. The results of the kinetics of phenol degradation indicated that degradation followed pseudo-first-order kinetics under different parameters. The thermodynamic kinetic studies also revealed a greater activation energy for Fe-MOF (1), whereas Fe-MOF (2) had a greater negative Gibbs energy, indicating greater spontaneity. This study highlights the application of iron-based metal-organic frameworks as catalysts for phenol degradation in wastewater.