The remarkable effect of Al–Fe pillaring on the adsorption and catalytic activity of natural Tunisian bentonite in the degradation of azo dye

Abstract

Four Al–Fe–PILC catalysts were prepared by pillaring process and tested for the degradation of diazo dye in heterogeneous Fenton-like process. The synthesized catalysts were characterized using XRD, N2 sorption, XRF and TEM techniques in order to study the influence of iron and Al loading on structure and texture. In this work, at Fe loading of 10%, pillared clay was studied and investigated in catalytic test. The effects of major parameters, such as initial pH, H2O2 concentration and catalyst dose were tested on the activity as well as iron leaching from catalyst. Results of this study show that dye degradation rate increased with an increase in dosages of catalyst and concentration of H2O2 up to a certain limit. However, the degradation rate decreased with an increase in the pH. Mineralization and comparison with different catalysts prepared were evaluated by analyzing color removal and inorganic ions (SO4 2−, NO3 −) concentrations. The kinetic studies revealed that the degradation profile is well fitted by the first-order kinetic model.