title: [Photodegradation of UV filter PABA in nitrate solution].
abstract: The aqueous photolysis of a UV filter p-aminobenzoic acid (PABA) using Xe lamp as simulated solar irradiation source was investigated in the presence of nitrate ions. The effects of pH, concentration of nitrate ions and concentration of humic substance in natural water on the photodegradation of PABA were studied. The results showed that photodegradation of PABA in nitrate solution followed the first order kinetics. The increasing concentration of nitrate ion increased favored the photodegradaton of PABA, of which the first order constant increased from 0.002 2 min(-10 to 0.017 9 min(-1). The photodegradation of PABA promoted with the increase of pH while the increasing concentration of humic substance showed inhibiting effect. Hydroxyl radicals determined by the molecular probe method played a very importnant role in the photolysis process of PABA. Photoproducts upon irradiation of PABA in nitrate solution were isolated by means of solid-phase extraction (SPE) and identified by LC-MS techniques. The probable photoinduced degradation pathways in nitrate solution were proposed.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, China. mengcui6@163.com
authors.forename: Cui
authors.initials: C
authors.lastname: Meng
authors.forename: Yue-Fei
authors.initials: YF
authors.lastname: Ji
authors.forename: Chao
authors.initials: C
authors.lastname: Zeng
authors.forename: Xi
authors.initials: X
authors.lastname: Yang
mesh_terms: D010129:4-Aminobenzoic Acid / Q000737:chemistry*; D006812:Humic Substances; D009566:Nitrates / Q000737:chemistry*; D010782:Photolysis; D013473:Sunscreening Agents / Q000737:chemistry*; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D006812:Humic Substances; D009566:Nitrates; D013473:Sunscreening Agents; D014874:Water Pollutants, Chemical; D010129:4-Aminobenzoic Acid