In-situ uv absorption spectroscopy for observing dissolved ozone in water

Abstract

Ozonated water was investigated using a conventional UV-Vis spectrophotometer. We compared the UV absorption spectra of ozone (O3) in water generated by either O2 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 O2 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 O2. As increase of the ozonation time, it noted that the absorption spectrum indicated the presence of high concentration of H2O2 and O2 as well as relatively lower concentration of O3.