In-situ UV Absorption Spectroscopy for Observing Dissolved Ozone in Water

Ozonated water was investigated using a conventional UV-Vis spectrophotometer. We compared the UV absorption spectra of ozone (O-3) in water generated by either O-2 or air plasma bubbling method. The results noted that the observing the entire absorption spectrum is important for understanding the composition of ozonated water. Using an in-situ with an O-2 plasma bubbling in water we monitored the time-resolved UV absorption spectrum of the ozonated water. It is well known that a typical UV absorption spectrum of ozonated water contains a broad absorption peak at 260 nm and a shoulder below 220 nm. In our time-resolved measurement, however, it initially contained a broad absorption at short wavelength range below 210 nm considerably from dissolved O-2. As increase of the ozonation time, it noted that the absorption spectrum indicated the presence of high concentration of H2O2 and O-2 as well as relatively lower concentration of O-3.