ABSTRACT
Sulfonamide antibiotics are often detected in terrestrial and aquatic environment, but little is known about abiotic degradation of these antibiotics. In the present study, the degradation of the sulfonamide antibiotic sulfadiazine by a synthesized δ-MnO2 was investigated. The initial reaction rate of sulfadiazine oxidized by manganese dioxide increased as the solution pH decreased by weakening electrostatic attraction between sulfadiazine and MnO2 and enhancing the reduction potential of MnO2. The presence of metal ions (Mn2+, Na+ and Ca2+), especially Mn2+, decreased the initial reaction rate by competitively adsorbing and reacting with MnO2. Two different products were identified during the reaction of sulfadiazine with MnO2 and the transformation of parent compound started with the formation of sulfadiazine radicals. Furthermore, toxicity assay results showed that the toxicity of products produced by bacteria decreased with elapse of reaction time. Results from the present study indicate that manganese dioxides in environmental matrix could be helpful in dissipation of sulfadiazine released into the environment.
Funding
This work was financially supported by the Hunan Provincial Natural Science Foundation of China (13JJ3155), the China Postdoctoral Science Foundation (2014M562104), the Scientific Research Fund of Hunan Provincial Education Department (15A130), the Startup Foundation for Doctors of Hunan University of Arts and Science (BSQD1004) and the Construct Program of the Key Discipline in Hunan Province (Applied Chemistry).