Ceria-promoted heterogeneous Fenton-like oxidation of polyvinyl alcohol, Rhodamine-B, and Reactive Red X-3B over Fe/Cu@γ-Al2O3 microspheres under neutral conditions

Abstract

To improve the catalytic activity and stability of a copper-iron-based Fenton-like system, the element cerium was added to the Cu-Fe-based catalyst via spray drying-calcination method. Polyvinyl alcohol (PVA) was chosen as the target pollutant to evaluate the properties of the ceria-promoted Fe/Cu@γ-Al2O3 (Ce-Fe/Cu@γ-Al2O3) microspheres. The experimental results showed that the PVA removal rate reached 99.74% in the Ce-Fe/Cu@γ-Al2O3/H2O2 system. After 10 consecutive catalytic reactions, the PVA removal rate was still maintained above 96%. Comparative experimental results showed that the addition of Ce significantly improved the catalytic activity and stability of the Cu-Fe-based catalyst. In addition, this catalytic system also showed good degradation efficiency for Rhodamine-B and Reactive Red X-3B dyes, with removal rates reaching 99.97% and 99.94%, respectively. The mechanism of the synergistic effect of Cu, Fe, and Ce was established, and electron paramagnetic resonance (EPR) experiments revealed that hydroxyl (·OH), superoxide (O2·-), and singlet oxygen (1O2) radicals were involved in the catalytic degradation of PVA. This study demonstrates a novel spray drying-calcination method for the preparation of Ce-Fe/Cu@γ-Al2O3 microspheres with outstanding catalytic activity and stability in Fenton-like systems. The Ce-Fe/Cu@γ-Al2O3 catalyst prepared in this research provides a potential alternative for the efficient removal of organic pollutants in wastewater.