Calcination temperature effects on the physicochemical properties of copper-based wire-meshes: The implications in the CWPO of phenol

Abstract

This work investigates phenol elimination from water through the Catalytic Wet Peroxide Oxidation (CWPO) reaction using CuO/TiO2-ZrO2 supported on wire-meshes, all with 5 wt.% Cu and calcined at different temperatures. These were characterized by SEM/EDX, elemental mappings, XRD, LRS and XPS, and their mechanical stability was studied. The increment in the calcination temperature generated less reducible Cu2+ species, which impacted in phenol conversion rate, slowing it down. Particularly, when the lower temperatures were applied (500 – 800 °C), copper was found well-distributed on the support and high mineralization values (above 85%) were obtained. Nevertheless, these high TOC conversions were the result of elevated copper leaching (∼ 40 ppm), markedly contributing as a homogeneous catalyst. Contrarily, the application of more extreme temperatures, such as 850 and 900 °C, led to the migration of copper to the inner part of the coating, and consequently to lower copper leaching (7.6 and 0.9 ppm, respectively), due to a protective effect of the support. Accordingly, the corresponding mineralization degrees were lower, 60 and 40%, respectively. An adequate temperature was found (850 °C), with higher mineralization and better mechanical resistance than the catalyst calcined at 900 °C.