A comparison of Al-Fe and Zr-Fe pillared clays for catalytic wet peroxide oxidation

摘要

Catalysts based on pillared clays with Al,Zr and Al-Fe and Zr-Fe have been synthesized from a commercial bentonite and tested for catalytic wet peroxide oxidation (CWPO) using phenol as target compound at 298 K.The Al-Fe pillared clay showed a higher activity than the Zr-Fe one for phenol oxidation,although the second was more active for H_2O_2 decomposition.Fairly different values of apparent activation energy were obtained for this last reaction with these two types of catalysts,suggesting that the prevailing pathway in H_2O_3 decomposition is different.The higher activity of the Al-Fe pillared clay for CWPO suggests that this catalyst favours the generation of OH radicals,whereas with the Zr-Fe one H_2O_2 decomposes predominantly to O_2 which has a low oxidation capacity at the mild operating conditions commonly used in Fenton oxidation.