KINETICS OF WET OXIDATION OF IMIDAZOLE OVER RU/C CATALYST

The heterocyclic aromatic amine, imidazole (or IM), was chosen as a model compound for studying wet oxidative destruction of wastewaters contaminated with nitrogenous organic compounds. In a three-phase slurry reactor, commercial Ru/C catalyst was employed in the 473-503 K range. The partial pressure of oxygen (O2) was varied between 0.34 and 1.38 MPa, whereas catalyst loading (ω) was varied between 0.01 and 0.04 kg/m3. The influence of reaction conditions on the degradation of total organic carbon (TOC) was studied and it was found that the performance of the selected catalyst was promising. Kinetic data on TOC disappearance were obtained in a chemical control regime and modeled using a two-step power-law model and a Langmuir-Hinshelwood-type dual-site model with slow surface reaction between adsorbed TOC and atomically adsorbed O2. From a record of the conversion of the nitrogen atom in IM into various species, it was discovered that NO3- and molecular N2 were prevalent at high temperature (503 K) while NH4+ ions were mainly formed at low temperature (473 K). This work will assist the design of reactors used for wet air oxidation of wastewaters polluted by nitrogenous organic impurities.