Synthesis of Ce-La-Pr/Mn-O Ternary Oxide Composites via Co-Precipitation and Synergistic Photocatalytic Degradation of Cr(VI)

Abstract

This study utilized a straightforward co-precipitation method to successfully synthesize Ce-La-X(Mn/Pr)-O composite materials for treating simulated hexavalent chromium (Cr(VI)) wastewater with distinctively porous and fluffy textures, along with tubular morphologies. Notably, Ce-La-Mn-O demonstrated a remarkable specific surface area of 96.2698 m2/g, mesoporous architecture with a pore diameter of 6.9511 nm, and an impressive adsorption capacity of 88.79 mg/g. Under optimized conditions, specifically an initial Cr(VI) concentration of 20 mg/L, a Ce-La-Mn-O dosage of 0.8 g/L, a reaction temperature of 40 °C, an initial pH of 6, and with the application of simulated daylight, the removal rate of Cr(VI) exceeded 98% within 15 min. Even after three cycles, the removal rate was maintained at above 80%. Based on a comprehensive suite of morphological, structural, and performance characterizations, the introduction of Mn/Pr was found to modify the structure of Ce-La-O and enhance the synergistic interactions among the metals within the Ce-La-O framework. In addition, Ce-La-Mn-O exhibited superior visible light absorption properties and dual functionality for catalytic reduction and adsorption. All three materials were found to form -OH polar bond functional groups, converting it to Cr(III) and subsequently forming Cr(OH)3. The Ce-La-X(Mn/Pr)-O composite materials provide a robust theoretical foundation for exploring the dual functional synergistic effects in the efficient removal of Cr(VI) from aqueous systems, indicating their vast potential for practical applications.