| 氯酚溶液的γ辐照还原降解研究 |
| 摘要点击 3831 全文点击 1794 投稿时间：2012-06-21 修订日期：2012-09-05 |
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| 中文关键词 氯酚 γ辐照 还原降解 水合电子 脱氯 |
| 英文关键词 chlorophenols Gamma irradiation reductive degradation hydrated electron dechlorination |
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| 中文摘要 |
| 氯酚由于氯取代基产生的诱导效应,使其容易受到亲核粒子的攻击而被还原降解. 通过测定γ辐照前后氯酚母体、Cl-离子以及反应中间产物的浓度变化,研究了4种氯酚水溶液(4-CP、2-CP、2,4-DCP、2,4,6-TCP) 与水合电子eaq-反应的降解脱氯过程. 结果表明,在水合电子eaq-还原体系中,4种氯酚的降解脱氯顺序依次为:2,4,6-TCP＞2,4-DCP＞2-CP＞4-CP,多氯酚比单氯酚容易降解脱氯,邻位上的氯原子要比对位上的氯原子更容易去除,苯酚和Cl-是氯酚反应降解的最终产物. 另外,4种氯酚的降解和脱氯过程皆遵循一级反应动力学特征,4-CP、2-CP、2,4-DCP和2,4,6-TCP的降解反应常数分别是0.154、0.253、0.750和1.188 kGy-1,脱氯反应常数分别为0.137、0.219、0.251和 0.306 kGy-1. |
| 英文摘要 |
| Because chlorine is an electron withdrawing group, the highly chlorinated phenols may react quickly with hydrated electrons rather than with hydroxyl radicals. The process of reactions of four chlorophenols (4-CP, 2-CP, 2,4-DCP, 2,4,6-TCP) with eaq- was investigated in aqueous solutions by detecting the concentration of CPs, Cl- and intermediates. In the eaq-reductive system, the experimental results showed that the order of four kinds of chlorophenol degradation and dechlorination was 2,4,6-TCP＞2,4-DCP＞2-CP＞4-CP. The greater the chlorine content was the higher reactivity of hydrated electrons towards chlorophenols was. Furthermore, hydrated electrons may preferentially attack the ortho-position of chlorine atom rather than the para-position of chlorine atom. Phenol and Cl- were detected as the final product of the reductive reaction. Additionally, processes of degradation and dechlorination of CPs were observed as the pseudo-first-order kinetics. The reaction constant of degradation of 4-CP, 2-CP, 2,4-DCP and 2,4,6-TCP were 0.154, 0.253, 0.750 and 1.188 kGy-1, respectively. Meanwhile, the dechlorination of 4-CP, 2-CP, 2,4-DCP and 2,4,6-TCP were 0.137, 0.219, 0.251 and 0.306 kGy-1, respectively. |
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