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

Abstract

Abstract Ferrite magnetic nanoparticles are active in the advanced oxidation process (AOP), which catalyzes the decomposition of H2O2 generating reactive oxygen species (ROS). Noble metal substitution is an efficient strategy to improve the catalytic activity of ferrite-based catalysts. In this study, Cd0.5Cu0.5−xAgxFe2O4 (where 0 ≤ x ≤ 0.5) ferrites were fabricated via 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 single-phase cubic spinel structure in all the synthesized samples. The crystallite size was in the nanoregime (7–15 nm), and it decreased similarly to the saturation magnetization 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. Cd0.5Cu0.5−xAgxFe2O4 exhibited excellent catalytic performance in the whole pH range of 2–11, especially in the strong alkaline environment. Cd0.5Cu0.5−xAgxFe2O4 was a promising efficient and stable material for Fenton-based alkaline wastewater treatment. Finally, the pathway includes, HO•, HO2−•, O2−• as oxidants resulted from the synergistic effects of Fe3+, Cu2+, and Ag+, with H2O2 and surface hydroxyl groups has been proposed.