Heterogeneous Photo-Fenton Oxidation of Methylene Blue Solution Using Fe(II)-Montmorillonite Calcinated Clay Catalyst

Abstract

Textile wastewaters are very problematic if released into the environment without proper treatment. Due to their recalcitrant nature, chemical treatments such as Advanced Oxidation Processes are often used. Among AOPs, Fenton-based processes presented promising results. However, considering the drawbacks associated with homogeneous Fenton, the aim of this work was to develop a heterogeneous catalyst using montmorillonite clay as the base material. After the application of an impregnation method, the Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction analysis showed the successful impregnation of iron into the montmorillonite clay. The catalyst Fe(II)-Mt was tested under different settings, and results showed that the best operational conditions (pH = 3.0, [Fe(II)-Mt 0.5M] = 1.0 g/L, [H2O2] = 4 mM, [MB] = 0.16 mM, radiation = UV-C (254 nm), time = 25 min) allowed to achieve 99.7% of Methylene blue (MB) removal. The catalyst showed great stability and was reused for three consecutive cycles. It can be concluded that Fe(II)-Mt catalyst is efficient for MB removal from aqueous solutions.