Han Y H, Ichikawa K, Utsumi H
Department of Bio-function Science, Faculty of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi, Fukuoka, Japan.
Water Sci Technol. 2004;50(8):97-102.
Ozone decomposition in aqueous solution proceeds through a radical type chain mechanism. These reactions involve the very reactive and catalytic intermediates O2- radical, OH radical, HO2 radical, OH-, H2O2, etc. OH radical is proposed as an important factor in the ozonation of water among them. In the present study, the enhancing effects of several phenolic compounds; phenol, 2-, 3-, 4-monochloro, 2,4-dichloro, 2,4,6-trichlorophenol on OH radical generation were mathematically evaluated using the electron spin resonance (ESR)/spin-trapping technique. OH radical was trapped with a 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a stable adduct, DMPO-OH. The initial velocities of DMPO-OH generation in ozonated water containing phenolic compounds were quantitatively measured using a combined system of ESR spectroscopy with stopped-flow apparatus, which was controlled by homemade software. The initial velocities of DMPO-OH generation increased as a function of the ozone concentration. The relation among ozone concentration, amount of phenolic compounds and the initial velocity (v0) of DMPO-OH generation was mathematically analyzed and the following equation was obtained, v0 (10(-6) M/s) = (A' x [PhOHs (10(-9) M)] + 0.0005) exp (60 x [ozone (10(-9) M)]). The equation fitted very well with the experimental results, and the correlation coefficient was larger than 0.98.
臭氧在水溶液中的分解通过自由基型链式反应机理进行。这些反应涉及非常活泼的催化中间体，如超氧阴离子自由基（O₂⁻）、羟基自由基（OH）、过氧化氢自由基（HO₂）、氢氧根离子（OH⁻）、过氧化氢（H₂O₂）等。其中，羟基自由基被认为是水中臭氧氧化过程中的一个重要因素。在本研究中，利用电子自旋共振（ESR）/自旋捕集技术，对苯酚、2-氯苯酚、3-氯苯酚、4-氯苯酚、2,4-二氯苯酚、2,4,6-三氯苯酚等几种酚类化合物对羟基自由基生成的促进作用进行了数学评估。羟基自由基用5,5-二甲基-1-吡咯啉-N-氧化物（DMPO）捕获，形成稳定加合物DMPO-OH。采用ESR光谱仪与停流装置联用的系统，并通过自制软件控制，定量测定了含酚类化合物的臭氧化水中DMPO-OH生成的初始速率。DMPO-OH生成的初始速率随臭氧浓度的增加而增大。对臭氧浓度、酚类化合物含量与DMPO-OH生成初始速率（v₀）之间的关系进行了数学分析，得到如下方程：v₀（10⁻⁶ M/s）=（A'×[PhOHs（10⁻⁹ M）]+0.0005）exp（60×[臭氧（10⁻⁹ M）]）。该方程与实验结果拟合良好，相关系数大于0.98。
