Ruthenium-based catalysts were prepared by a saturation-dip method. Their catalytic activity was evaluated by a catalytic wet oxidation (CWO) process. The ruthenium-based catalysts were used to purify organic pharmaceutical wastewater with high concentration pyridine and pyridine derivatives that have high chemical oxygen demand (COD). In the CWO process, organic pharmaceutical wastewater was continuously pumped into fixed-bed reactors filled with Ru-based catalysts, while the organic components in wastewater were catalytically degraded by oxygen at high temperatures and pressures (temperature, 170–300 °C; pressure, 1.0–10 MPa). The experimental results showed that the prepared catalysts could effectively purify pharmaceutical wastewater with high concentration organic components, which are difficult to degrade biochemically, and that the removal rates of both COD and total nitrogen were over 99%.
Keywords: catalytic wet oxidation, pharmaceutical wastewater, pyridine, Ru/TiO2 catalyst, wastewater treatment