Response Surface Methodology for the Optimization of 4-Nitrophenol Degradation by a Heterogeneous Fenton-Like Reaction on Moroccan Pillared Clays

Heterogeneous Fenton-like reactions on pillared clays were investigated for the degradation of 4-Nitrophenol (4-NP). A Box–Behnken Design coupled with response surface methodology (RSM) was applied to evaluate and optimize the important variables. In this process, copper-pillared clays were prepared by intercalation of a Moroccan Bentonite and tested in the catalytic wet peroxide oxidation of 4-NP. The prepared catalysts were characterized by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Inductively coupled plasma atomic emission spectroscopy (ICP-AES). A significant quadratic model (P-value < 0.0008, R2 = 0.9526) was derived using analysis of variance (ANOVA), which was adequate to perform the process variables optimization. More than 90% of 4-NP was experimentally degraded after 4 h of reaction time under the optimum conditions. The model predicted maximum removal of 98.66% of 4-NP under the optimum conditions of operational parameters (9.48 mM peroxide concentration, 0.325 g L−1 catalyst dose and 51 ℃).