Catalytic wet peroxide oxidation of phenol over Ce-Zr-modified clays: Effect of the pillaring method

Preparation, characterization and catalytic activity of Zr-and Ce-Zr pillared clays with different method (direct, indirect, and under reflux), starting from Tunisian interstratified illite-smectite bentonite, are described. Zirconium pillared clays (Zr-PILC) revealed weaker thermal stability. To overcome this drawback, the addition of cerium (Ce) as the second metal component to Zr-PILC was attempted. Wet peroxide oxidation of phenol from industrial wastewaters was carried out over these catalysts. The catalysts were very efficient in the phenol oxidation reaction in diluted aqueous medium under mild experimental conditions (298 K and atmospheric pressure). The addition of Ce in the synthesis step of the inorganic polycations yielded a favorable effect on the pillaring of the materials, allowing the increase of the basal spacing and enhancing the catalytic activity of the solids. The pillared clays were characterized by XRD, chemical analysis, CEC, and N-2 adsorption to 77 K. The acidity of the pillared clays was calculated from the adsorbed n-butyl amine.