Catalytic peroxidation of acrylic acid from aqueous solution incorporated with highly active La0.5Sr0.5BO3 (B=Cu, Fe and Ni) perovskite-like catalysts.

Abstract

In the current study, catalytic behaviour of La0.5Sr0.5BO3 (B=Cu, Fe and Ni) perovskite-like catalysts synthesized by sol-gel method were examined in catalytic peroxidation of acrylic acid as a model organic compound and further characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The effect of various parameters such as catalyst dose, H2O2/acrylic acid molar ratio, temperature, pH and initial acrylic acid concentration on acrylic acid and COD removal was studied. The maximum acrylic acid and COD removal of 86.79% and 71.57% were observed at optimum operating conditions (e.g., La0.5Sr0.5CuO3 catalyst dose = 600mg/L, stoichiometric molar ratio of H2O2/acrylic acid = 1.5, pH = 3, temperature 65°C and reaction time = 3h). The ROS scavenging studies were performed to identify in-situ generated reactive oxidant species, e.g., hydroxyl radicals (•OH), superoxide radicals (O2 •־) and singlet oxygen (1O2) and treated with their respective quencher during catalytic peroxidation of acrylic acid. Acrylic acid removal kinetics was performed by first order and Langmuir-Hinshelwood kinetic models. The plausible degradation mechanism was proposed based on intermediates identified by GC-MS analysis during catalytic peroxidation of acrylic acid.