title: Degradation of Thiamethoxam in aqueous solution by ozonation: Influencing factors, intermediates, degradation mechanism and toxicity assessment.
abstract: This paper focuses on the degradation of Thiamethoxam (THIA) in aqueous solution by ozonation. Four influencing factors: pH, THIA initial concentration, ozone concentration and temperature were investigated in order to optimize the conditions, and pH showed the greatest impact; the removal efficiency reached up to 71.19% under the condition of pH 5-11, THIA initial concentration 50-300 mg L(-1), the ozone concentration 10-22.5 mg L(-1) at 293-308 K after 90 min. Four main intermediates were separated and identified and the possible degradation mechanism was proposed. The luminous intensity of photobacteria and the chemical oxygen demand (COD) were measured to assess the changes of toxicity and mineralization in ozonation process, and results showed that the inhibition rate decreased by 60% and 76% of COD was removed after 180 min with the THIA initial concentration was 200 mg L(-1). Our study powerfully demonstrates that the degradation of THIA in aqueous solution by ozonation is a promising technology.
authors.affiliation: College of Chemistry and Material Science, Shandong Agricultural University, Tai'an 271018, China.
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Zhao
authors.affiliation: College of Chemistry and Material Science, Shandong Agricultural University, Tai'an 271018, China.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Ge
authors.affiliation: College of Chemistry and Material Science, Shandong Agricultural University, Tai'an 271018, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zuo
authors.affiliation: College of Chemistry and Material Science, Shandong Agricultural University, Tai'an 271018, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Shi
authors.affiliation: College of Chemistry and Material Science, Shandong Agricultural University, Tai'an 271018, China. Electronic address: shjia@sdau.edu.cn.
authors.forename: Shouhua
authors.initials: S
authors.lastname: Jia
mesh_terms: D001419:Bacteria / Q000187:drug effects; D057919:Biological Oxygen Demand Analysis; D006863:Hydrogen-Ion Concentration; D007306:Insecticides / Q000737:chemistry* / Q000633:toxicity; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000737:chemistry* / Q000633:toxicity; D010078:Oxazines / Q000737:chemistry* / Q000633:toxicity; D010126:Ozone / Q000737:chemistry*; D000077922:Thiamethoxam; D013844:Thiazoles / Q000737:chemistry* / Q000633:toxicity; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000633:toxicity
chemical_list: D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010078:Oxazines; D013844:Thiazoles; D014874:Water Pollutants, Chemical; D010126:Ozone; D000077922:Thiamethoxam
keywords: Intermediate; Mechanism; Ozonation; Thiamethoxam; Toxicity