Designing a Feasible Phenol Destruction Process Using LaM1−xCuxO3 (M = Co, Cr, Fe) Perovskites as Heterogeneous Fenton-Like Catalysts

Abstract

Phenol is one of the most toxic and carcinogenic oxygenated organic compounds, which is often found in wastewater of various industries. Therefore, design of efficient phenol degradation method becomes crucial. B-site substitution into perovskite structure generates synergistic effects in its structure which enhances catalytic properties. However, to effectively design an economically feasible process, substitution of cheap and catalytically active B-site metal elements becomes significant. In view of this, three perovskite-type oxides with chemical formula LaM0.5Cu0.5O3 (M = Co, Cr, Fe) were synthesized and characterized in this work. Furthermore, their application in a feasible phenol oxidation process has been reported. The XRD and XPS analysis results demonstrate successful B-site substitution of transition metal elements in perovskite structure. Remarkably high BET surface areas were obtained for all three catalysts (32–47 m2/g). The results of catalytic activity tests constructively reveal that LaCo0.5Cu0.5O3 is superior when compared with the other two catalysts. Highest TOC removal and best catalytic performance was exhibited by all the catalysts at 90 ℃, atmospheric pressure, 1 g/l catalyst loading and 700 rpm stirring speed. The reaction was successfully completed with hydrogen peroxide concentration less than the stoichiometric amount required for the reaction. The order of catalytic activity is LaCo0.5Cu0.5O3 > LaCr0.5Cu0.5O3 > LaFe0.5Cu0.5O3. This order of catalytic activity of the prepared catalysts can be attributed to high amount of lattice oxygen provided by LaCo0.5Cu0.5O3 catalyst, and the same conclusion can be drawn from the XPS analysis. This suggests that excellent catalytic performance can be attained at low costs for phenol oxidation process.