title: Thermo activated persulfate oxidation of antibiotic sulfamethoxazole and structurally related compounds.
abstract: The widespread occurrence of sulfonamides (e.g., sulfamethoxazole) in natural environment has raised growing concerns due to their potential to induce antibiotic-resistant genes. In this study, the degradation of SMX and related sulfonamides by thermo activated persulfate (PS) oxidation was investigated. Experimental results demonstrated that SMX degradation followed pseudo-first-order reaction kinetics. The pseudo-first-order rate constant (k(obs)) was increased markedly with increasing temperature and pH. The presence of bicarbonate manifested promoting effect on SMX degradation while fulvic acid reduced it. Radical scavenging tests revealed that the predominant oxidizing species was SO4(•-) at neutral pH. Aniline moiety in SMX molecule was confirmed to be the primary reactive site for SO4(•-) attack by comparison with substructural analogues. Reaction products were enriched by solid phase extraction (SPE) and analyzed by liquid chromatography-electrospray ionization-triple quadrupole mass spectrometry (LC-ESI-MS/MS). A total of 7 products derived from hydroxylation, sulfonamide S-N bond cleavage, aniline moiety oxidation and coupling reaction were identified, and transformation pathways of SMX oxidation were proposed. Degradation of sulfonamides was appreciably influenced by the heterocyclic ring present in the molecules. Results reveal that thermo activated PS oxidation could be an efficient approach for remediation of water contaminated by SMX and related sulfonamides.
authors.affiliation: College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: yuefeiji@njau.edu.cn.
authors.forename: Yuefei
authors.initials: Y
authors.lastname: Ji
authors.affiliation: College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Fan
authors.affiliation: College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Kuo
authors.initials: K
authors.lastname: Liu
authors.affiliation: Nanjing Institute of Environmental Science, Ministry of Environmental Protection of PRC, Nanjing 210042, China.
authors.forename: Deyang
authors.initials: D
authors.lastname: Kong
authors.affiliation: College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: jhlu@njau.edu.cn.
authors.forename: Junhe
authors.initials: J
authors.lastname: Lu
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000737:chemistry*; D006358:Hot Temperature; D007700:Kinetics; D010084:Oxidation-Reduction; D013420:Sulfamethoxazole / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D000814:Aniline Compounds; D000900:Anti-Bacterial Agents; D013431:Sulfates; D014874:Water Pollutants, Chemical; D013420:Sulfamethoxazole; C023650:aniline
keywords: Reaction products; Sulfate radical; Sulfonamides; Thermo activated persulfate oxidation; Transformation mechanisms