Fe₃O₄@Nico-Ag magnetically recyclable nanocatalyst for azo dyes reduction

Graphical abstract: - Highlights: • Fe₃O₄@Nico@Ag magnetic recyclable nanocatalyst (MRC) is more effective for the reduction of azo dyes consisting of MB and MO. • It could be reused several times without significant loss in catalytic activity. • Fe₃O₄@Nico@Ag (MRCs) has been successively used for colour reduction of MO, MB, EY, RhB and their mixtures. - Abstract: In this study, we report the successful synthesis of Fe₃O₄@Nico-Ag nanocomposite as magnetically recyclable nanocatalyst (MRCs) via reflux process at 80 °C for 5 h followed by reduction of Ag⁺. FeCl₃·6H₂O, FeCl₂·4H₂O, AgNO₃ as starting reactants and nicotinic acid as linker. The structure, morphology, thermal behaviour and magnetic properties of the product were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive spectrometry (EDX), thermal gravimetry (TG) and vibrating sample magnetometry (VSM), respectively. The catalytic activity of product for various azo dyes such as methylene blue (MB), methyl orange (MO), Rhodamine B (RhB) and eosin Y (EY) and their double mixtures were studied. It was found that Fe₃O₄@Nico-Ag MRCs is an efficient catalyst and can also rapidly separated from the reaction medium using magnet without considerable loss in its catalytic activity and used several times. Fe₃O₄@Nico-Ag MRCs has potential for the treatment of industrial dye pollutants.