Evaluation of synergistic approach of spinel cadmium–copper nanoferrites as magnetic catalysts for promoting wastewater decontamination: Impact of Ag ions doping

Metal substitution is an efficient strategy to improve the catalytic activity of ferrite-based catalysts. In this study, Cd(0.5)Cu(0.5−x)Ag(x)Fe(2)O(4) (where 0 ≤ x ≤ 0.5) ferrites were fabricated via a simple co-precipitation method. The influence of the silver ions on the structural, magnetic, and catalytic characteristics of the spinel nanoparticles, as well as on their morphology, was examined. X-ray diffractograms revealed a crystalline cubic spinel structure with crystallite sizes in the nanoregime (7–15 nm). The saturation magnetization reduced from 29.8 to 2.80 emu as the Ag(+) doping increased. Two prominent absorption bands were visible in Fourier-transform infrared spectra at 600 cm(−1) and 400 cm(−1), respectively, and they belonged to the tetrahedral (A) and octahedral (B) sites. The samples were then used as catalysts for the oxidative breakdown of the typical organic contaminant indigo carmine dye (IC). The catalytic process followed the first-order kinetic model, and the rate constant increased from 0.007 to 0.023 min(−1) with increasing of Ag(+) doping. Cd(0.5)Cu(0.5-x)Ag(x)Fe(2)O(4) exhibited excellent catalytic performance in the pH range of 2–11, which means that they are promising efficient and stable materials for Fenton-based alkaline wastewater treatment. Finally, the pathway includes, HO(•), HO(2)(−•), and O(2)(−)• as oxidants resulted from the synergistic effects of Fe(3+), Cu(2+), and Ag(+), with H(2)O(2) and surface hydroxyl groups have been proposed. GRAPHICAL ABSTRACT: [Image: see text]