title: Transient and steady-state photolysis of p-nitroaniline in aqueous solution.
abstract: Both transient photolysis and steady-state photo-degradation experiments were performed to gain insight into the kinetics and mechanisms of degradation of p-nitroaniline (p-NA) in aqueous solutions. Monophotonic photo-ionization of p-NA was characterized by 266 nm Laser Flash Photolysis (LFP). The quantum yield of e(aq)(-) was calculated. Radical cations and neutral radicals of p-NA were identified, respectively. The LFP of p-NA with H(2)O(2) in aqueous solutions was investigated for the first time. For steady-state photo-degradation, degradation of p-NA was observed at diverse irradiation conditions under 254 nm UV light. Direct photo-degradation of p-NA by 254 nm UV light in aqueous solution was very difficult. Once H(2)O(2) was added into the experimental system, degradation of p-NA was enhanced remarkably. In the absence of O(2), degradation rate increased rapidly along with the irradiation time and reached 80% at 10 min. p-NA could be totally removed after 15 min in UV/H(2)O(2) process. In the presence of O(2) and H(2)O(2), degradation rate increased linearly along with the irradiation time and reached 80% at 7.5 min. p-NA could be totally removed after 10 min. The mechanisms behind the photo-degradation of p-NA were discussed.
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, PR China.
authors.forename: Hongjuan
authors.initials: H
authors.lastname: Ma
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.forename: Changyong
authors.initials: C
authors.lastname: Pu
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Sufang
authors.initials: S
authors.lastname: Zhao
authors.forename: Side
authors.initials: S
authors.lastname: Yao
authors.forename: Jie
authors.initials: J
authors.lastname: Xiong
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry / Q000528:radiation effects*; D006861:Hydrogen Peroxide; D007700:Kinetics; D010100:Oxygen; D010782:Photolysis; D012996:Solutions; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000528:radiation effects*; D018508:Water Purification / Q000379:methods*
chemical_list: D000814:Aniline Compounds; D012996:Solutions; D014874:Water Pollutants, Chemical; C008625:nitroaniline; D006861:Hydrogen Peroxide; D010100:Oxygen