Oxidative Degradation of Organic Dyes Over Supported Perovskite Oxide LaFeO3/SBA-15 Under Ambient Conditions

Supported perovskite oxide, LaFeO3/SBA-15, is investigated for the first time as catalyst for the oxidation of organic dyes using hydrogen peroxide as oxidant. Characterizations such as XRD, XPS, TEM and N-2 physisorption isotherms indicate that the supported catalyst has typical perovskite LaFeO3 structure, and the ordered mesoporous structure of SBA-15 remains unchanged after the formation of LaFeO3. Catalytic tests indicate that LaFeO3/SBA-15 has large adsorption capacity, good catalytic performances, and wide working pH ranges (from 2 to 10) for the oxidation of dyes, e. g., Rhodamine B. Moreover, the catalyst can be reused for at least four times without appreciable loss in the activity, and no dissolved Fe3+ ion could be detected by atomic absorption spectrometry after the reaction, suggesting that LaFeO3/SBA-15 is a very stable and active catalyst for the oxidation of dyes in aqueous solution. Comparative tests on various organic dyes, such as reactive brilliant red X-3B, direct scarlet 4BS, methylene blue and Rhodamine B (RhB), indicate that LaFeO3/SBA-15 is more favorable for RhB oxidation, while considerable activity could also be available for other dyes, potentiating its wide applications for industrial removal of dyes. The excellent catalytic performances of LaFeO3/SBA-15 could be attributed to the synergistic effect between SBA-15 and LaFeO3.