Reductant free green synthesis of magnetically recyclable $MnFe_2O_4@SiO_2-Ag$ coreshell nanocatalyst for the direct reduction of organic dye pollutants

Abstract

The present paper describes in situ green immobilization of silver nanoparticles on $MnFe_2O_4@SiO_2$ nanospheres using Epilobium parviflorum (EP) without using any other toxic chemicals and reducing or stabilizing agents. The morphology, composition, and magnetic properties of the resulting $MnFe_2O_4@SiO_2-Ag$ core-shell nanocatalyst were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The catalytic performance of the synthesized $MnFe_2O_4@SiO_2-Ag$ was employed on the organic pollutants dyes such as rhodamine B (RhB) and methylene blue (MB). The results revealed significant reduction performances for the MB (116.28 s–1 g–1) and RhB (27.12 s–1 g–1) over the existing literature. Furthermore, the $MnFe_2O_4@SiO_2-Ag$ exhibited high stability for the completion of the reduction of RhB between the reaction times of 13.1 (first) and 19.8 min (final) with the 100% decolorization efficiency even after several cycles with an excellent magnetic separation. Overall, this work demonstrates a simple and practical green synthetic route for the preparation of magnetic recyclable core-shell nanocatalyst that can be a good candidate for the treatment of organic contaminants in wastewater adhering to green chemistry principles for the environmental pollution concerns.