Heterogeneous Fenton-like degradation of tartrazine using CuFe2O4 nanoparticles synthesized by sol-gel combustion

In this work, copper ferrite (CuFe2O4) nanoparticles (NPs) were prepared by sol-gel auto-combustion method and were used for the degradation of tartrazine in aqueous solution by heterogeneous Fenton-like process. The NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and point of zero charge measurement (pHPZC). XRD confirmed the tetragonal spinel structure of CuFe2O4. The average particle size evaluated by Debye Scherrer equation was found to be 37.34 nm. FTIR spectrum shows two primary absorption bands characteristic of the spinel ferrites. The point of zero charge of the CuFe2O4 catalyst was about 6.9. Response surface methodology (RSM) was employed for the optimization of the degradation efficiency of tartrazine. Four important process parameters including catalyst loading (0.1–0.5 g/L), tartrazine concentration (30–50 mg/L), H2O2 concentration (35.28–70.56 mM) and temperature (30–50 °C) were optimized using the statistical Box-Behnken design. A quadratic model was developed and validated by the analysis of variances. Numerical optimization by desirability function was applied to identify the optimum conditions for maximum degradation efficiency of tartrazine. The optimum conditions were determined as 0.32 g/L of catalyst loading, 64.35 mM of H2O2, 30.63 mg/L of tartrazine concentration and 49.92 °C of temperature. The degradation efficiency of the catalyst remains stable after five times recovery and reuse.