Engineered cobalt-doped magnetic MOF@Ag₂O nanocomposites for adsorptive removal of polycyclic musk pollutants

Abstract

The present study focuses on the green synthesis, characterization, and adsorptive performance of cobalt-doped MOF@Ag₂O nanocomposites for the efficient removal of polycyclic musk fragrance contaminants namely Galaxolide and Tonalide from contaminated water. Methods: The Ag₂O nanoparticles were synthesized through a green chemical precipitation method using Ficus carica L. leaf extract. The Co-MOF was prepared through solvothermal coordination method and Co-MOF@Ag₂O nanocomposite was fabricated through microwave-assisted integration and was characterized through XRD, FTIR, SEM, TEM, BET, VSM, TGA, and zeta potential analysis. Characterization confirms the successful formation of nanocomposite with nanoscale structure (~26.9 nm), and high colloidal stability (−32 mV). XRD pattern confirms the crystalline structure of both Ag₂O and Co-MOF components and EDX reveal its elemental composition that highlights the presence of Co and Ag, along with plant-derived biomolecules aiding green synthesis. Batch adsorption experiments were performed to evaluate the removal efficiency in different conditions. Highest removal was achieved at pH 5 for Tonalide and pH 6 for Galaxolide under the best doses of 20 mg/100 mL and 30 mg/100 mL, respectively. Kinetic studies show that both compounds obeyed pseudo-second-order kinetics with high correlation coefficients (R² = 0.9989 for Tonalide, 0.999 for Galaxolide), which confirms chemisorption as the prevailing mechanism. The Q_e values were 105.41±0.263 mg/g and 110.10±0.115 mg/g for Tonalide and Galaxolide, respectively. The nanocomposite shows high reusability with high adsorption efficiency up to five cycles. Work emphasizes the application of Co-MOF@Ag₂O nanocomposites as an environmentally friendly, high-performance, sustainable adsorbent for the removal of stable synthetic musk compounds in wastewater treatment processes.