Preparation of highly efficient and stable Fe,Zn,Al-pillared montmorillonite as heterogeneous catalyst for catalytic wet peroxide oxidation of Orange II

Fe,Zn,Al-pillared montmorillonite (Mt) were prepared by ion exchange reaction. Effect of the Fe/Zn molar ratio in Fe,Zn,Al-pillaring solution on the structural properties of Fe,Zn,Al-Mt was examined. Characterization studies were performed by N2-adsorption/desorption, ICP, FTIR, DR UV–Vis spectroscopy and XRD. The interlayer space, specific surface and volume of micropores of pillared-Mt was 18.8 Å, 157 m2 g−1 and 0.114 cm3 g−1 respectively. Besides, the catalytic performance of Fe,Zn,Al-Mt was analyzed through wet peroxide oxidation of Orange II under mild experimental condition. The results indicated that the catalytic performance of Fe,Zn,Al-Mt was affected by the Fe/Zn molar ratio as following pattern: the obtained pillared solids with lower Fe/Zn molar ratios exhibited better catalytic performance and less iron leaching during the reaction. Moreover, the introduction of zinc into Mt shortened the induction time of reaction and improved the catalytic behaviour. Throughout this work, the chemical oxygen demand removal of OII was 77.1 % after the solution treated by Fe,Zn,Al(3/7)-Mt (defined as the Fe/Zn molar ratio of 3/7 in the pillaring solution) catalyst at temperature of 60 °C and atmospheric pressure of 1 atm.