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 °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.