Copper ferrite-graphene oxide catalyst for enhanced peroxymonosulfate activation and pollutant degradation

Abstract

In this study, a magnetic nanocomposite of copper ferrite (CuFe₂O₄) supported on reduced graphene oxide (rGO) was synthesized via a solvothermal method and applied as a catalyst for the activation of peroxymonosulfate (PMS) to degrade Orange G (OG) dye in aqueous solution. The structure and morphology of the catalyst were thoroughly characterized using XRD, FTIR, SEM, STEM, and nitrogen adsorption-desorption analyses. The rGO/CuFe₂O₄ composite demonstrated superior catalytic performance, achieving 90.8% OG removal within 60 minutes, attributed to its enhanced surface area, efficient radical generation, and strong interaction between rGO and CuFe₂O₄. The system exhibited high activity across a wide pH range, significant mineralization (78% TOC removal), and good recyclability over four cycles. The catalyst also effectively degraded other dyes including rhodamine B (78%), methylene blue (86%), and methyl orange (89%) under similar conditions. These findings suggest that rGO/CuFe₂O₄ is a promising, reusable catalyst for advanced oxidation processes in wastewater treatment.

Fig. 1. Schematic illustration of the hydrothermal synthesis of rGO/CuFe₂O₄ nanocomposite.

Fig. 2. XRD patterns of CuFe₂O₄ and rGO/CuFe₂O₄ samples.

Fig. 3. FTIR spectra of graphene oxide (GO), CuFe₂O₄ and rGO/CuFe₂O₄ samples.

Fig. 4. Nitrogen adsorption/desorption isotherm of CuFe₂O₄ and rGO/CuFe₂O₄ samples.

Fig. 5. SEM images of (a) CuFe₂O₄ and (b) rGO/CuFe₂O₄ samples.

Fig. 6. STEM images of (a and b) CuFe₂O₄ and (c and d) rGO/CuFe₂O₄ samples.

Fig. 7. Particle size distribution analysis of (a) CuFe₂O₄ and (b) rGO/CuFe₂O₄.

Fig. 8. (a) Removal efficiency of OG in different system, Reaction conditions: [catalyst] = 0.2 g L⁻¹; [PMS] = 2 mM; [OG] = 50 mg L⁻¹; initial pH without adjustment. Effects of operating parameters on OG degradation (b) PMS dosage, (c) catalyst dosage, and (d) various pH conditions.

Fig. 9. pH point zero charge (pH_PZC) of rGO/CuFe₂O₄.

Fig. 10. (a) Degradation of various organic dyes using the rGO/CuFe₂O₄–PMS system. (b) Discoloration and mineralization (TOC removal) of OG at different reaction times under optimal conditions. Reaction conditions: [catalyst] = 0.2 g L⁻¹; [PMS] = 2 mM; [OG] = 50 mg L⁻¹, [BM] = 10 mg L⁻¹; [RhB] = 10 mg L⁻¹; [MO] = 10 mg L⁻¹.

Fig. 11. Recycling tests of the rGO/CuFe₂O₄ catalyst; reaction conditions: [catalyst] = 0.2 g L⁻¹; [PMS] = 2 mM; [OG] = 50.

Fig. 12. The effect of scavengers on OG degradation using different scavengers.

Fig. 13. Proposed mechanism of orange G degradation in the rGO–CuFe₂O₄/PMS system.