Sibunit-based catalytic materials for the deep oxidation of organic ecotoxicants in aqueous solutions. III: Wet air oxidation of phenol over oxidized carbon and Rr/C catalysts

This article presents the first systematic study concerning the effect of the oxidative treatment conditions on the surface chemical composition and the catalytic properties in the deep wet oxidation of organic ecotoxicants of a Sibunit type carbon material (S4) which was earlier identified as promising for the oxidative treatment of industrial wastewaters. The influence of the surface chemistry of the carbon materials oxidized under different conditions on the catalytic performances in the wet air oxidation of phenol of the bare carbon materials as well as the ruthenium-containing catalysts (3 wt % Ru) supported on the oxidized carbon samples was studied. The catalytic activity of the bare carbon samples appeared to be moderate and either (i) increased with the total number of carbonyl and phenolic surface groups or (ii) decreased with the total concentration of surface carboxylic and lactonic species. However, the catalytic performances of the Ru-containing catalysts were significantly higher. Based on our results, an optimum pretreatment of the carbon support could be identified to obtain the most stable and active Sibunit-supported ruthenium catalysts in the wet air oxidation of phenols.