苯甲腈类有机污染物在水中光化学降解的研究

以５００Ｗ中压汞灯为光源，对２１种苯甲腈类化合物在水溶液中的光化学降解（下简称光解）进行了研究。结果表明，该类化合物的光解符合一级动力学反应方程，半衰期均小于３５ｍｉｎ。实验证明存在基态电荷转移络合物（ＣｈａｒｇｅＴｒａｎｓｆｅｒＣｏｍｐｌｅｘ，下简称ＣＴＣ），并认为是引起光氧化反应的重要因素。苯环上斥电子取代基、腐殖酸、一些无机盐、酸性或碱性介质、温度等均能加快反应，但吸电子取代基会减慢反应、本文还以日光为光源对几种苯甲腈类化合物在天然水中进行了光解研究，表明光解速率较慢，推测反应主要是水中可溶解有机物（下简称ＤＯＭ）的光敏化所致。

A FUNCTIONAL STUDY ON PHOTODECOMPOSITION OF BENZONITRILIC COMPOUNDS IN AQUEOUS SOLUTION

Photodecomposition of 21 benzonitrilic compounds in aqueous solution (or natural water) has been studied under a 500W middle-pressure mercury lamp and sunlight. Results show that the photolysis half-life of these compounds under the Hg lamp is less than 35 min, and the photodecomposition rate of the compounds in natural water is slower under sunlight. All of the photodecompositions are first--order reaction. The photolysis reactions can be promoted under the following conditions: (1) some inorganic salts present in the aqueous solution, such as NaCl, KCl,KBr and Na2CO3; (2) in the acidic (pH <4) or basic (pH> 10)medium; (3) humic acids, especially prepared from natural water; (4) at higher temperature of solution and (5) electrophilic functional groups present in the benzene ring of the benzonitrilic compounds. With the mechanism of charge transfer comples (CTC) formed in the pho-todecomposition reactions and the photosensitive effect, the results of our experiments can be satisfactorily expalined.