Ferrite-based catalysts for peroxymonosulfate activation: comparative study of RB KN-R degradation

Ferrite-based catalysts are promising for enhancing peroxymonosulfate (PMS) activation to degrade refractory organic pollutants such as synthetic dyes. This study evaluated the catalytic performance of CuFe₂O₄, CoFe₂O₄, ZnFe₂O₄, MnFe₂O₄, and NiFe₂O₄ for reactive brilliant blue KN-R degradation. The novelty of this work lies in CuFe₂O₄’s use as a superior PMS activator, leveraging Cu²⁺/Cu⁺ and Fe³⁺/Fe²⁺ redox cycling to enhance SO₄•⁻ generation, offering superior efficiency, cost-effectiveness, and catalyst recovery. CuFe₂O₄ demonstrated the highest degradation efficiency (99.10%) within 5 min under optimized conditions (catalyst dosage: 50 mg/L, PMS: 400 mg/L, dye: 120 mg/L, pH: 6.4, and temperature: 25°C), supported by the highest rate constant (k = 0.9512 min⁻¹). Comparative results showed CoFe₂O₄, MnFe₂O₄, ZnFe₂O₄, and NiFe₂O₄ achieving lower efficiencies of 82.00%, 67.31%, 43.80%, and 16.57%, respectively. Characterization (X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy) confirmed the structural and surface properties driving CuFe₂O₄’s performance, including its stability and reusability, maintaining over 90% activity after five cycles. This study establishes CuFe₂O₄ as a highly efficient, scalable, and sustainable catalyst for PMS activation, offering a promising solution for wastewater treatment and environmental remediation.