Removal of sulfonamide antibiotics from wastewater by gamma irradiation in presence of iron ions

The presence of sulfonamide antibiotics in aquatic environments has received increasing attention in recent years. Sulfadiazine (SD), a widely used heterocyclic sulfonamide pharmaceutical, has entered into the receiving water body. In this paper, gamma rays are used to irradiate samples of sulfadiazine antibiotics-containing wastewater. The results demonstrate that SD can be effectively degraded by irradiation, but the mineralization degree of SD (in terms of TOC) is not as efficient as the SD degradation. The addition of Fe²⁺ can significantly enhance the SD degradation and mineralization through the generation of hydroxyl radical by catalytic decomposition of H₂O₂ from water radiolysis. Ion chromatography analysis indicates that sulfate ions (SO₄^2-) and formate (HCOO^-) are the main intermediate products. Gamma irradiation is a promising technology for removing low-concentration antibiotics from water and wastewater. (authors)