Unveiling the photocatalytic activity of Cu/Fe2O3@gC3N4 nanosheet as an efficient fenton-like catalyst for reactive blue 19 removal: Optimization and kinetics studies

Abstract

In this work, a Cu/Fe₂O₃@g-C₃N₄ nanocomposite was synthesed using the thermal decomposition of urea as a carbon and nitrogen precursor to remove the reactive blue 19 (RB-19) in aqueous solution by the Fenton process. The obtained material was characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray (EDX) analysis and EDX-mapping techniques. The results obtained confirmed that the material was indeed doped with Cu and Fe with a crystalline structure. A central composite design was used to optimize the degradation factors. The optimal conditions were obtained at a pH of 3, with a catalyst mass of 75 mg, an initial pollutant concentration of 100 mg/L and a H₂O₂ concentration of 1 mol/L, with a respective degradation percentage of 96 %. The reusability of the catalyst allowed to observe that it retains its catalytic activity with a degradation rate higher than 84 % after five cycles. The degradation kinetics of RB-19 allowed to have R² values close to 1 for the influence of pH. The pseudo-first and second order kinetic models were studied, with rate constants ranging from 1.7x10⁻³ to 5.3x10⁻³ min⁻¹ and 3.6x10⁻⁶ to 7.3x10⁻⁴ L/mg.min, respectively for a pH. According to this study, it was confirmed that the H₂O₂/catalyst (Cu/Fe₂O₃@g-C₃N₄) nanocomposite could be an effective and resistant means to treat wastewater containing RB-19.