Synthesis and characterization of CoFe₂O₄/SiO₂/Cu-MOF for degradation of methylene blue through catalytic sono-Fenton-like reaction

Successful catalytic degradation of pollutant molecules in wastewater streams has received tremendous attention in the last decade. Herein, we report the synthesis and characterization of a Fenton-like catalyst nanocomposite including CoFe₂O₄ magnetic nanoparticles, porous silica and Cu-metal–organic framework (Cu-MOF) via a multi-step self-assembly method. For this purpose, CoFe₂O₄/SiO₂ magnetic nanostructure was synthesized by sol–gel method and then functionalized by glutaric anhydride and 3-(triethoxysilyl)propylamine. Subsequently, a nanoporous Cu-MOF framework was grown on the surface of nanoparticles to gain CoFe₂O₄/SiO₂/Cu-MOF nanostructure. This unique nanocomposite offers various functional sites for the successful catalytic treatment of wastewater, confirmed by different analytical characterization techniques. The as-designed nanocomposite catalyst showed a porous structure with 27 g/m² surface area. The as-synthesized nanocomposite was used to degrade methylene blue in its aqueous solution as a model wastewater sample through a sono-Fenton-like reaction approach. The results showed that almost all (∼98%) of the methylene blue molecules were degraded in the model wastewater sample an hour. Additionally, we analyzed the catalytic kinetic data by several mathematical models. The analysis revealed that the catalytic process follows a pseudo-second-order kinetic model, indicating that the removal of dye took place dominantly through the multi-site interactions, thanks to different active sites on the surface of the as-synthesized nanocomposite. This study shows that the proposed nanoporous magnetic MOF nanostructure has a great potential to be used as a catalyst for environmental applications.