Electron spin resonance analyse on the production of hydroxyl radicals by ozone photolysis

In order to explore the production of hydroxyl radical (·OH) in a confined space, a novel ozone-light irradiation system is constructed in this study, and the ·OH radical is measured by spin-trapping electron spin resonance (ESR) method in which 5,5-dimethyl-1-pyrroline- N -oxide (DMPO) is selected as the spin-trap. Several influence factors including the light intensity, the irradiation time and DMPO mass concentration are discussed. The results show that in this experimental system, with DMPO mass concentration of 1g/L and the irradiation time of 30 min, the ·OH radical can be best captured. Besides, both wavelength and intensity of the irradiation light could effect the generation of ·OH radical. These results are of great importance to further study the sterilization effect of ·OH radical in confined space.