| dc.description.abstract | This thesis studied the use of a bi-metallic Cu and Mg catalyst dispersed on γ-Al2O3 for the
complete oxidation of a naphthenic acid (NA) model compound, trans-4-
pentylcyclohexanecarboxylic acid (4PCH) by ozone. Mono-metallic Cu and Mg, and bimetallic Cu-Mg catalysts were tested for the ozonation of 4PCH. The catalysts were
characterized by ICP-OES, BET, SEM, TEM, XRD, NH3-TPD and XPS. It was found that
bi-metallic catalysts with high amount of surface hydroxyl groups and with pHpzc close to
the pH of the solution at 8.5 were suitable for the mineralization of 4PCH. The catalyst with
1 and 5 wt% of Cu and Mg loading, respectively, had the highest activity with 90% total
organic carbon (TOC) removal at a dosage of 2 g/L in 120 min. The use of tert-butyl
alcohol (TBA) confirmed the involvement of OH•
radicals in the oxidation mechanism of
4PCH. Mg fine-tuned the pHpzc of the catalyst and provided a high concentration of
neutrally charged surface hydroxyl groups to generate reactive oxygen species (ROS) to
break down 4PCH in the liquid bulk. Cu participated in the complete oxidation of smaller
carboxylic acid molecules through complexation and surface reactions with adsorbed ROS.
The by-products of the oxidation of 4PCH were identified and a reaction network was
proposed based on a meta-addition mechanism. The most active catalyst retained its TOC
removal over 5 reusability cycles with an average Cu, Mg, and Al leaching of 0.07, 1.30
mg/L, and 0.2, respectively. The best performing catalyst was also proven effective for the
complete oxidation of a mixture of 4 NA model compounds with an electric energy per
order of 78.1 kWh/m3. | en_US |
