Catalytic activity of LaCu0.5Mn0.5O3 perovskite at circumneutral/basic pH conditions in electro-Fenton processes

Abstract

A great challenge in electro-Fenton processes is the development of active heterogeneous catalysts at circumneutral or even basic pH in order to avoid the acidification of the wastewater effluents and the generation of an undesirable metallic sludge after the treatment. In this work, LaCu0.5Mn0.5O3 perovskite has been assessed as heterogeneous electro-Fenton catalyst for the removal of methylene blue dye as model pollutant. The catalyst has been tested in a wide range of pH, from acidic (3) to basic (8.5) values. The effect of the catalyst loading, the applied voltage and the air flow was also studied on the efficiency of the electro-Fenton process. LaCu0.5Mn0.5O3 showed a remarkable activity at circumneutral and basic pH, even at the low current density studied of 2.6–0.9 mA/cm2. The durability of the catalyst was also assessed for five successive runs. XRD patterns of the reused catalyst evidenced a high stability of the perovskite structure after the several runs. The low copper leaching of the catalyst in the aqueous phase (< 0.05 mg/L for Cu) also proves the stability of the LaCu0.5Mn0.5O3 perovskite material and its main contribution as heterogeneous catalyst to the overall activity of the electro-Fenton system.