Mutiple Pharmceuticals Adsorption, Oxidation and Catalytic Chlorination by Metal Oxides ( II )

Many kinds of pharmaceuticals have been found in the environment recently. They may be toxic for human and aquatic species. Adsorption or oxidation by metal oxides such as manganese oxide is one of the important naturally sinks of the pharmaceuticals. Disinfection by chlorine is a common process in drinking water and wastewater treatment. Free chlorine can oxidize some kinds of pharmaceuticals. Metal oxides can be used as a heterogeneous catalyst for ozonation. The removal of ozonation and the mineralization of the organic pollutants can be enhanced by metal oxides. A lot of researches have been done about the single kind of pharmaceutical adsorption or oxidation by metal oxides or chlorination by free chlorine. The wastewater, however, usually contains various pharmaceuticals. This study tried to investigate the removal of the mixed pharmaceuticals by the adsorption and oxidation of manganese oxide and the heterogeneous catalyst effect for chlorination of hypochlorite was also investigated. Three most frequently detected pharmaceuticals, acetaminophen, diclofenac, and sulfamethoxazole were chosen to conduct the experiments. The results reveal that pH significantly influenced the removal of pharmaceuticals by manganese oxide. All the three pharmaceuticals can be effectively removed at acidic condition. Only acetaminophen can be removed at alkaline condition. Increasing the dosage of manganese dioxide and raising the temperature increased the removal of drugs. The adsorption and oxidation of the acetaminophen and sulfamethoxazole characteristics by manganese oxide did not change with the addition of hypochlorite. While the adsorption and oxidation rate of diclofenac increased significantly at neutral condition with the addition of hypochlorite. The results of Electron Spectroscopy for Chemical Analysis (ESCA) revealed that as pH increasing, the Mn(II) proportion increase on the particle’s surface. UPLC-Q-TOF-MS was used to identify oxidation products. At acidic condition, diclofenac has a oxidation product. At alkaline condition, dimer and timer of acetaminophen were found. There was no new products was found with he addition of hypochlorite.