光助非均相芬顿体系中羟基自由基的荧光光谱法测定与影响因素研究

以TiO2/Al2O3为载体制备了Fe2O3/TiO2/Al2O3催化剂,建立了三相流化床光助非均相芬顿反应体系.选取香豆素为羟基自由基捕获剂,采用荧光法检测光助非均相芬顿反应体系中产生的活性中间体,发现在体系中有高活性的羟基自由基生成.实验讨论了溶液的pH值、H2O2投加量、催化剂投加量、光强对光助非均相芬顿反应体系中羟基自由基生成量的影响.结果表明,以香豆素为羟基自由基捕获剂的实验方法可以较好地检测不同实验条件下光助非均相芬顿反应体系中产生的羟基自由基,且该光助非均相芬顿反应体系中羟基自由基的生成在30 min内符合零级反应动力学.溶液的pH值、H2O2投加量、催化剂投加量、光强均对反应体系中羟基自由基的生成存在一定的影响.

Detection of Hydroxyl Radical in Heterogeneous Photo-Fenton System Using the Fluorescence Technique and Influencing Factor Study

The Fe_2O_3/TiO_2/Al_2O_3 catalyst was prepared by using TiO_2/Al_2O_3 as carrier and the heterogeneous photo-Fenton system was established in the three-phase fluidized bed. A fluorescence technique was developed for the determination of the hydroxyl radicals (·OH) from the heterogeneous photo-Fenton system, using coumarin as the fluorescence probe. In addition, four main factors, namely pH, H_2O_2 concentration, catalyst loading and UV light intensity, which could influence the concentration of ·OH produced during the reaction process, was also discussed. The fluorescence method using coumarin as the fluorescence probe was demonstrated to be capable of detecting ·OH generated in heterogeneous photo-Fenton system with veracity and high reproducibility. It was also found that the ·OH generated in heterogeneous photo-Fenton system conformed to the zero reaction dynamics in 30 min. Moreover, the pH, H_2O_2 concentration, catalyst loading and UV light intensity influenced the ·OH generated during the reaction process.