Persulfate activation over CoFe₂O₄/CuS for degradation of Orange II under visible light

A magnetic porous composite catalyst has been synthesized from CoFe₂O₄ and CuS. Its degradation performance towards organic pollutants in a heterogeneous photocatalytic system has been compared with those of the individual photocatalysts and those of individual chemocatalysis systems. Orange II served as a target contaminant. Persulfate and catalyst were combined under visible light conditions to achieve degradation of the organic pollutant, whereupon the degradation efficiency reached up to 97 %. The catalyst has been characterized by X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) analysis, Mott–Schottky analysis, scanning electron microscopy (SEM), and solid-state UV/Vis spectrophotometry. The influences of pH and different catalyst and persulfate loadings in the system have been studied. The results of quenching experiments showed non-radical degradation to be a major pathway, with singlet molecular oxygen (¹O₂) and photogenerated holes (h⁺) as the critical reactive species. Besides, the magnetic properties of the catalyst are conducive to its recycling, and it still showed high degradation efficiency after three cycles.