AWWA WQTC52919

The iodide/iodate actinometer is based on the ultraviolet (UV) photolysis of theiodide/iodate complex in a pH 9.2 buffered solution, where the iodate acts as anelectron acceptor. The product is the triodide ion which has a well definedabsorption band with a maximum at 352 nm. The iodide/iodate complex absorbssignificantly in the UV range from 200-300 nm, and then the absorption dropssharply at wavelengths above 300 nm. Thus the actinometer covers the biocidalwavelength range very well. In addition, the actinometer is very easy to use, isinsensitive to room light, and the analysis is based on a direct measurement ofthe absorbance at 352 nm of the UV irradiated solution. In this study, theactinometer was applied to the determination of the fluence rate distribution ina UV reactor, where the fluence rate is the omni-directional equivalent of theirradiance. Includes 3 references, tables, figures.