Photocatalytic, electrochemical and photoelectrocatalytic degradation of the reactive dye Turquoise Tiafix R2G using LaFeO3 perovskite

Original scientific paper

Abstract

In this study, the photocatalytic, electrochemical and photoelectrocatalytic performance of lanthanum ferrite (LaFeO₃) toward the degradation of the dye Turquoise Tiafix R2G was investigated. LaFeO₃ was synthesized via a sol-gel route and characterized by XRD, N₂ adsorption (BET) and SEM, confirming its perovskite structure. Photolysis experiments indicated that the dye is highly photostable under the irradiation conditions employed. In photocatalysis, different LaFeO₃ loadings (0.1, 0.2 and 0.3 g L⁻¹) were tested under a 100 W halogen lamp, with 0.3 g L⁻¹ providing the highest removal, although the process remained limited by electron-hole recombination. In heterogeneous electro-oxidation with LaFeO₃ in suspension, current densities of 10, 15 and 20 mA cm⁻² were applied; 15 mA cm⁻² afforded the best compromise between activity and stability, significantly increasing the dye oxidation rate. The simultaneous application of irradiation and current in the photoelectrocatalytic process led to the highest efficiency, achieving approximately 95% degradation within 60 min. These results demonstrate a clear synergistic effect between photocatalytic reactive oxygen species generation in the LaFeO₃ suspension and electrochemical oxidant generation at the anode, resulting in a more effective oxidative environment. Thus, the optimized photoelectro­catalytic condition (0.3 g L⁻¹ LaFeO₃ and 15 mA cm⁻²) is a promising strategy for the treatment of effluents containing industrial dyes.