焦化废水中难降解有机毒物光催化氧化机理的探讨

The Mechanism of Photacatalytic Oxidation of Nonbiodegradable Toxic Organic Substances in Coking Wastewater

焦化废水中的多环芳烃（PAH）等有机毒物经多相光催化氧化,彻底分解成CO2。反应发生在催化剂的表面,主要是自由基型反应,O2变成激发单线态O2后参与反应。反应受温度的影响非常敏感,反应的有效光源为低压汞灯,光和热之间存在协同效应。反应条件下,苯并[a]蒽（BaA）分解的速率常数为3.477mg/L。反应过程概括为:反应分子在催化剂表面上的吸附,氧化性自由基和O2的形成,有机物的氧化,和氧化产物的脱附与扩散。

The mechanism of heterogeneous photocatalytic oxidation of organic substances has been further discussed by the photo—catalytic oxidation reactions of nonbiodegradable toxic orga nic substances in coking wastewater. Polycyclic aromatic hydrocarbons (PAH) and other toxic organic substances are thoroughly dissolved in CO_2 by heterogeneous photocatalytic oxidation. These reactions occurring on the surface of the catalyst are mainly free radical reactions in which O_2 participates after it is transformed into single linear state O_2~. These reactions are extremely sensitive under the influence of temperature. The efficient light source is a low—voltage mercury lamp. Cooperating effect exists between light and temperature. Under the conditions of reactions benzo [a] anthrancene (BaA) dissolving rate—constant is 3.477mg/L. h. The whole process of reactions is sunmmrized as follows; the adsorption of reaction molecules on the surface of catalyst; the formation of oxidizing free radicals and O_2~; the oxidalion of organic substances; and desorption and diffusion of oxidated products.