Catalytic Oxidation of Naphthalene Using a Pt/Al2O3 Catalyst with Ozone

This study investigated the application of catalytic oxidation process with ozone to decompose polycyclic aromatic hydrocarbons (PAHs). The process is noted as ozone-catalytic oxidation (OZCO). Naphthalene (Nap), which is the simplest and lowest toxic PAH, was taken as a target compound. The emission of Nap to the atmosphere was generally found from waste incineration or diesel engine combustion. Pt/Al2O3 catalyst was used to facilitate OZCO process. The relationships between the conversion of Nap (XNap) and related factors such as reaction temperature (T), space velocity (SV), and concentration of ozone (CO3) were examined. Furthermore, the corresponding reaction mechanisms and the roles of catalysts and ozone were discussed. The results indicated that the required reaction temperatures for effective decomposition of Nap decreased with the increase of inlet concentration of ozone (CO3,in) at the same conversion level of Nap. Regarding the temperature at conversion of 50% (T50), there was an approximate reduction of 20 K for the case of OZCO process with CO3,in of 1750 ppmv (T50 = 460 K) compared to the process without ozone (T50 = 480 K). The value of mineralization extent of Nap (MNap) with respect to the complete conversion of Nap to CO2 can reach as high as 95% at 490 K with CO3,in in the range of 900–1750 ppmv. Thus, OZCO process is effective for the mineralization of Nap.