B-site Substitution Effects on The Catalytic Activity of Perovskites Compounds towards Oxidative Degradation of Orange II Solutions

Abstract

Perovskite is known as potential decent ceramic metal oxides catalyst for wastewater treatment particularly in catalytic oxidation process. Perovskites can be uniquely and chemically tailored due to its simple structure which able to accommodate wide range of A and/or B-site cations. In this work, detailed investigations on the substitution effect of different B-site cations into the main structure of perovskite compounds towards catalytic oxidation of orange II solution were performed. Four (4) different types of B-site metal cations (Cu, Ni, Mo and Co) were substituted into perovskites structure via a combined EDTA-citric acid complexation method. The reactivity of resultant perovskites was found to be in sequence of Na0.27Ca0.48Cu0.25O3 > Na0.25Ca0.48Ni0.27O3 ≍ Na0.09Ca0.29Mo0.62O3 > Na0.02Ca0.33Co0.39O3 in the absence of stimulant or oxidant during 2 hours heterogeneous reaction. Interestingly, Na0.09Ca0.29Mo0.62O3 perovskites catalyst exhibited superior catalytic activity by having complete Orange II removal (≍99%) in the presence of oxidant (0.022M H2O2) within 15 min of reaction. The reactivity of B-site perovskites catalysts changed significantly in presence of oxidant during heterogeneous reaction that can be represented as Na0.09Ca0.29Mo0.62O3> Na0.27Ca0.48Cu0.25O3>Na0.02Ca0.33Co0.39O3>Na0.25Ca0.48Ni0.27O, respectively. Such findings confer tunable and unique catalytic properties of B-site perovskites catalysts in enhancing the oxidative degradation of recalcitrant dye contaminated wastewater effluents.