Copper and iron-based monolithic catalysts for phenol Catalytic Wet Peroxide Oxidation (CWPO): Support and iron effects on the catalytic performance

Water is an invaluable resource of our planet, and our lives and those of the future generations rely on it. Phenolic compounds are part of many industries effluents and they are highly toxic and not biodegradable. Therefore, they could be eliminated from water through the Catalytic Wet Peroxide Oxidation (CWPO) reaction. In this work, alumina-supported and cordierite-supported copper and iron-based monolithic catalysts were synthesized and tested in the CWPO of phenol. These structured catalysts were characterized by stereoscopic microscopy, N2 adsorption, XRD, LRS, SEM/EDX and XPS, and their mechanical resistance was analyzed. The effect of both, the support and the presence of iron as a co-active phase on the metal species leaching, and therefore on the catalytic performance, were evaluated. Alumina-supported copper species were more accessible and reducible than cordierite-supported ones and, as a consequence, these rapidly converted the totality of phenol and achieved high mineralization and COD reduction. On the other hand, iron addition as a co-active phase decreased copper leaching in all cases due to Cu-Fe interactions. The bimetallic alumina-supported catalyst exhibited the best catalytic performance with low copper and iron leachings. Consequently, it was tested in a more complex reaction media (tap water). This catalyst resulted promising, converting all the phenol with high mineralization and COD reduction, although suffering some copper and iron leaching.