Enhanced photocatalytic degradation of dyes and antibiotics with biosynthesized FeMn2O4 nanocomposite under sunlight irradiation: isotherm and kinetic study

This study reports the biosynthesis of FeMn2O4 nanocomposite (NC) using an aqueous leaf extract of Artemisia. The FeMn2O4 NC was characterized by zeta potential, SEM, XRD, and FTIR. X-ray diffraction analysis confirmed that the biosynthesized FeMn2O4 NC has a cubic crystal nature with a crystallite size of 28.45 nm. Scanning electron microscopy images showed that the FeMn2O4 NC has a spherical shape. The optical bandgap energy of the FeMn2O4 NC was estimated to be approximately 2.94 eV for direct bandgap and 1.27 eV for indirect bandgap. The photocatalytic activity of the FeMn2O4 NC was evaluated for the degradation of amoxicillin and cephalexin antibiotics under sunlight irradiation, resulting in a degradation efficiency of 99% for both drugs. The FeMn2O4 NC also exhibited excellent degradation efficiency against Congo Red (CR) and Methylene Blue (MB) dyes with about 83.23% and 100%, respectively, after just 40 min. The reaction kinetic calculations showed that the absorption of both dyes and antibiotics by the adsorbent followed a pseudo-first-order model. The equilibrium isotherms revealed that the amoxicillin and cephalexin absorption process through the synthesized magnetic nanocomposite was consistent with the Langmuir model. These findings suggest that the FeMn2O4 NC can serve as a promising absorbent for the removal of amoxicillin and cephalexin antibiotics as well as MB and RC dyes from aqueous solutions.