title: [Effect of different forms of inorganic nitrogen on the photodegradation of antipyrine in water].
abstract: The photodegradation performance and mechanisms of antipyrine (ANT, a member of anti-inflammatory analgesics) under simulated irradiation using a 300 W Xenon lamp were explored in this study. And the variation of the photodegradation of ANT in the presence of different forms of nitrogen and different pE values in the aqueous environment were also investigated. The results demonstrated that ANT photodegradation proceeds via pseudo first-order kinetics in all cases. Photodegradation of ANT in water occurs through direct photodegradation and self-sensitization via reactions with hydroxyl radical (*OH) and singlet oxygen (1O2). Presence of different forms of inorganic nitrogen (NH4+, NO2- and NO3-) showed rather different effects. At low pE value (< 5), NH4+ was the main form of inorganic nitrogen, and little effect was observed on ANT photodegradation. With the increase of pE value from 4.82 to 6.85, nitrogen form changed from NH4+ to NO2- accordingly, and the inhibiting effect increased gradually due to their competitive absorption for the irradiation and NO2- acting as a scavenger of *OH. At pE 6.85, NO2- was the main form of inorganic nitrogen, which showed a maximum inhibiting rate of 35.31%. When the pE value continued to increase from 6.85 to 8.15, the nitrogen form changed from NO2- to NO3-, and the suppression effect on ANT photodegradation decreased.
authors.affiliation: Beijing Key Laboratory for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China. 15824830792@126.com
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhao
authors.forename: Chao
authors.initials: C
authors.lastname: Chen
authors.forename: Li
authors.initials: L
authors.lastname: Feng
authors.forename: Li-Qiu
authors.initials: LQ
authors.lastname: Zhang
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000302:isolation & purification; D000983:Antipyrine / Q000302:isolation & purification*; D007287:Inorganic Chemicals / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D017672:Nitrogen Compounds / Q000737:chemistry; D010782:Photolysis / Q000187:drug effects*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D007287:Inorganic Chemicals; D017672:Nitrogen Compounds; D014874:Water Pollutants, Chemical; D009584:Nitrogen; D000983:Antipyrine