17种多环芳烃在水溶液中的光解
PHOTODEGRADATION OF 17 PAHs IN METHANOL(OR A CETONITRILE)-WATER SOLUTION
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摘要: 本文以国产高压汞灯及太阳光为光源,系统地研究了常见的17种多环芳烃(下简称PAH)在甲醇-水、乙腈-水溶液中的光化学降解。结果表明,大多数PAH的光解速率常数(k)与它们的极谱氧化半波电位(E1/2ox有关:E1/2ox值低(易氧化),则k值大(反应快)。黑暗条件下的对照试验未发现PAH降解。还测得了萘的光解产物为邻苯二甲酸,并发现溶液中的溶解氧除去后萘不能光解。这些都表明大部分PAH光解为光氧化反应。另外,用电荷转移复合物(CTC)的形成、解离和单重态氧(1O2)的氧化机理,讨论了温度高、助溶剂极性强会加快光解速率的效应。Abstract: Photolysis rate constants (k) and half-life time(t1/2) of 17 PAHs in CH3-OH(or CH3CN)-H2O solution were determined under high-pressure mercury lamp or sunlight. Results showed that the lower the oxidation-half-wave potential (E1/2ox), the higher the k; and that phthalic acid was the photodegra-tation product of naphthalene. With the mechanism of charge transfer complex and singlet oxygen oxidation, the effects of temperature and cosolvent polarity on k values were discussed.
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