[Detection of hydroxyl radical in heterogeneous photo-Fenton system using the fluorescence technique and influencing factor study].

The Fe2O3/TiO2/Al2O3 catalyst was prepared by using TiO2/Al2O3 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, H2O2 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, H2O2 concentration, catalyst loading and UV light intensity influenced the *OH generated during the reaction process.