Catalytic Ozonation of Oxalic Acid in the Presence of Fe2O3-Loaded Activated Carbon

The activity and optimum condition of metal-loaded activated carbon catalyst (Me/AC) for oxalic acid (OA) ozonation were evaluated. Results showed that Fe-loaded activated carbon (Fe/AC) showed better activity in five kinds of Me/AC catalysts prepared by a dipping method. Fe catalyst, crystallizing as gamma-Fe2O3, dispersed well on AC surface. Fe2O3/AC, with 1.12% Fe weight ratio and 450 degrees C calcination temperature and showed better activity for OA ozonation. 89.2% of OA was removed in the Fe2O3/AC/O-3 process, which was higher than those in AC/O-3 (79.6%) and O-3 (3.2%) processes. The calcination process helped to promote adsorption capability and catalytic activity of AC. In addition, Surface hydroxyl groups played a key role in Fe2O3/AC's catalytic activity. Acidic condition was more favorable for OA removal in the Fe2O3/AC/O-3 process. A hydroxyl radical (center dot OH) oxidation mechanism was proven in Fe2O3/AC/O-3. The catalytic activity of Fe2O3/AC remained satisfactory after several cycles, indicating that Fe2O3/AC had a good reusability property.