Boosting the catalytic activity of nanostructured ZnFe2O4 spinels incorporating with Cu2+ for photo-Fenton degradation under visible light.

Methylene blue (MB) is hazardous in natural water because this dye causes serious diseases that endangers public health and ecosystems. Photocatalytic degradation is a prominent technique for achieving the effective elimination of dye pollutants from wastewater and contribute vitally to ecology and environmental safety. Herein, Cu2+-substituted ZnFe2O4 nanomaterials (CuxZn1-xFe2O4; x = 0, 0.1, 0.2, 0.3, 0.4, 0.6) were synthesized, characterized, and applied for the photocatalytic degradation of MB dye beneath visible light with the assistance of hydrogen peroxide (H2O2). The feature of the photo-catalysts was determined by XRD, EDX, FTIR, DRS, BET, SEM, and TEM techniques. Incorporation of Cu2+ ions changed the crystalline phase, particle size, morphology, and surface area. The photocatalysis condition was optimized with the following major factors, the amout of doping Cu2+ ions, H2O2 concentration, adsorbent dosage, and MB concentration. As a result, the photocatalytic MB degradation efficiency by Cu0.6Zn0.4Fe2O4 catalyst was 99.83% within 90 min under LED light (λ ≥ 420 nm), which was around 4 folds higher than that of pure ZnFe2O4. The photo-Fenton kinetics were in accordance with the pseudo-first-order kinetic model (R2 = 0.981), giving the highes rate constant of 0.034 min-1. It can be, therefore, concluded that Cu2+ substitution considerably boosted the photocatalytic activity of CuxZn1-xFe2O4 ZnFe2O4, suggesting a bright prospect of Cu0.6Zn0.4Fe2O4 as a photo-catalyst in the dyes wastewater treatment.