| 防晒剂对氨基苯甲酸在硝酸根溶液中的光解研究 |
| 摘要点击 1313 全文点击 1405 投稿时间：2010-10-22 修订日期：2010-12-09 |
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| 中文关键词 防晒剂 对氨基苯甲酸 光解 硝酸根 活性氧 |
| 英文关键词 UV filter p-aminobenzoic acid(PABA) photodegradation nitrate ion reactive oxygen species |
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| 中文摘要 |
| 以氙灯为模拟太阳光光源，研究了防晒剂分子对氨基苯甲酸（PABA）在硝酸根溶液中的光解，探讨了pH值、硝酸根离子的浓度和天然水体中广泛存在的腐殖质浓度对防晒剂PABA光解速率的影响.结果表明，PABA在硝酸根溶液中的光解反应符合一级动力学规律，PABA的光化学反应速率随硝酸根离子浓度的提高显著增大，其速率常数可由0.0022 min-1增至0.0179 min-1；提高溶液pH能促进PABA的间接光解，而加入Suwannee河腐殖酸（SRHA）和富里酸（SRFA）对PABA的间接光解产生抑制作用.采用甲醇和异丙醇作为自由基分子探针鉴定了·OH在PABA光解过程中起了重要作用，采用SPE-LC-MS方法鉴定了PABA的光解产物，并提出了PABA在硝酸根溶液中可能的光解途径. |
| 英文摘要 |
| 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 0.0022 min-1 to 0.0179 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. |
