von Gunten Urs
Swiss Federal Institute for Environmental Science and Technology, EAWAG, Ueberlandstr 133, CH-8600 Dübendorf, Switzerland.
Water Res. 2003 Apr;37(7):1443-67. doi: 10.1016/S0043-1354(02)00457-8.
The oxidation of organic and inorganic compounds during ozonation can occur via ozone or OH radicals or a combination thereof. The oxidation pathway is determined by the ratio of ozone and OH radical concentrations and the corresponding kinetics. A huge database with several hundred rate constants for ozone and a few thousand rate constants for OH radicals is available. Ozone is an electrophile with a high selectivity. The second-order rate constants for oxidation by ozone vary over 10 orders of magnitude, between < 0.1 M(-1)s(-1) and about 7 x 10(9) M(-1)s(-1). The reactions of ozone with drinking-water relevant inorganic compounds are typically fast and occur by an oxygen atom transfer reaction. Organic micropollutants are oxidized with ozone selectively. Ozone reacts mainly with double bonds, activated aromatic systems and non-protonated amines. In general, electron-donating groups enhance the oxidation by ozone whereas electron-withdrawing groups reduce the reaction rates. Furthermore, the kinetics of direct ozone reactions depend strongly on the speciation (acid-base, metal complexation). The reaction of OH radicals with the majority of inorganic and organic compounds is nearly diffusion-controlled. The degree of oxidation by ozone and OH radicals is given by the corresponding kinetics. Product formation from the ozonation of organic micropollutants in aqueous systems has only been established for a few compounds. It is discussed for olefines, amines and aromatic compounds.
臭氧化过程中有机和无机化合物的氧化可通过臭氧、羟基自由基或二者的组合发生。氧化途径由臭氧和羟基自由基浓度的比例以及相应的动力学决定。有一个包含数百个臭氧反应速率常数和数千个羟基自由基反应速率常数的庞大数据库。臭氧是一种具有高选择性的亲电试剂。臭氧氧化的二级反应速率常数在10个数量级范围内变化，介于<0.1 M⁻¹s⁻¹和约7×10⁹ M⁻¹s⁻¹之间。臭氧与饮用水相关无机化合物的反应通常很快，通过氧原子转移反应发生。有机微污染物可被臭氧选择性氧化。臭氧主要与双键、活化芳香体系和未质子化胺反应。一般来说，供电子基团增强臭氧氧化，而吸电子基团降低反应速率。此外，直接臭氧反应的动力学强烈依赖于形态（酸碱、金属络合）。羟基自由基与大多数无机和有机化合物的反应几乎是扩散控制的。臭氧和羟基自由基的氧化程度由相应的动力学决定。水体系中有机微污染物臭氧化的产物形成仅在少数化合物中得到确定。针对烯烃、胺和芳香化合物进行了讨论。
