光催化氧化技术利用光激发氧化将O2、H2O2等氧化剂与光辐射相结合。所用光主要为紫外光，包括uv-H2O2、uv-O2等工艺，可以用于处理化工废水中CHCl3、CCl4、多氯联苯等难降解物质。另外，在有紫外光的Fenton体系中，紫外光与铁离子之间存在着协同效应，使H2O2分解产生羟基自由基的速率大大加快，促进有机物的氧化去除。
Photocatalytic oxidation combines oxidants such as O 2 and H 2 with light radiation by photo-induced oxidation. Ultraviolet light, including UV-H_2and UV-O_2, can be used to treat refractory substances such as CHCl_3, CCl_4 and PCBs in chemical wastewater. In addition, in Fenton system with ultraviolet light, there is a synergistic effect between ultraviolet light and iron ions, which greatly accelerates the rate of hydroxyl radicals produced by the decomposition of hydrogen peroxide and promotes the oxidative removal of organic compounds.
所谓光化学反应，就是只有在光的作用下才能进行的化学反应。该反应中分子吸收光能被激发到高能态，然后电子激发态分子进行化学反应。光化学反应的活化能来源于光子的能量。在太阳能利用中，光电转换以及光化学转换一直是光化学研究十分活跃的领域。 80年代初，开始研究光化学应用于环境保护，其中光化学降解治理污染尤受重视，包括无催化剂和有催化剂的光化学降解。前者多采用臭氧和过氧化氢等作为氧化剂，在紫外光的照射下使污染物氧化分解；后者又称光催化降解，一般可分为均相、多相两种类型。均相光催化降解主要以Fe2＋或Fe3＋及H2O2为介质，通过光助-芬顿(photo－Fenton）反应使污染物得到降解，此类反应能直接利用可见光；多相光催化降解就是在污染体系-空穴对，吸附在半导体上的溶解氧、水分子等与电子-空穴作用，产生•OH等氧化性极强的自由基，再通过与污染物之间的羟基加合、取代、电子转移等使污染物全部或接近全部矿质化，最终生成CO2、H2O及其它离子如NO3－、PO43－、SO42-、Cl－等。与无催化剂的光化学降解相比，光催化降解在环境污染治理中的应用研究更为活跃。
The so-called photochemical reaction is a chemical reaction that can only be carried out under the action of light. In this reaction, the absorbed light energy of the molecule is excited to the high energy state, and then the molecule of the electron excited state reacts chemically. The activation energy of photochemical reaction comes from the energy of photons. In the utilization of solar energy, photoelectric conversion and photochemistry conversion have been very active areas of photochemistry research. In the early 1980s, the application of photochemistry in environmental protection was studied. Particular attention was paid to photochemistry degradation for pollution control, including photochemistry degradation without and without catalysts. The former mostly uses ozone and hydrogen peroxide as oxidants to oxidize and decompose pollutants under the irradiation of ultraviolet light; the latter, also known as photocatalytic degradation, can generally be divided into two types: homogeneous and heterogeneous. Homogeneous photocatalytic degradation mainly uses Fe2+, Fe3+, and H2O2 as the medium, and the pollutants are degraded by photo-Fenton reaction, which can directly utilize visible light. Multiphase photocatalytic degradation is the interaction of dissolved oxygen and water molecules adsorbed on semiconductors with electron-hole in the polluted system-hole pair to produce highly oxidized free radicals such as OH, and then OH. Through hydroxyl addition, substitution and electron transfer with pollutants, all or nearly all of the pollutants are mineralized, resulting in CO 2, H 2 and other ions such as NO3-, PO43-, SO42-, Cl-, etc. Compared with photocatalytic degradation without catalyst, the application of photocatalytic degradation in environmental pollution control is more active.