Wet peroxide oxidation of phenol over Cu-ZSM-5 catalyst in a flow reactor. Kinetics and diffusion study

Abstract

The wet peroxide oxidation of phenol over the extruded 1.5%Cu/(80%H-ZSM-5+20%Al2O3) catalysts of the different geometric forms and sizes (cylinders with diameters 1, 2, 3mm, trefoils, spheres and monoliths with size of channels 1.0×1.0, 1.5×1.5mm) was studied in a flow reactor. The geometric form and size of the catalyst granules exert a pronounced effect on the apparent kinetics of the process. The highest efficiency toward phenol destruction was observed for the catalysts with a greater geometric surface area (trefoils and monolith with high channel density). The conversions of phenol and TOC at flow rate 5mLmin−1 equal to 100 and ∼90% were achieved over these catalysts. Application of the spherical shape catalyst with lowest geometric surface gave only 80% conversion of phenol at the same reaction conditions. The proposed mathematical model of the process, accounting for internal and external diffusion limitations on the base of the pseudo-first order simplification of the apparent kinetic rates, provide reasonably accurate description of the experimental data and reproducing all important process regularities.