Decolorization of Humate Solution by Ozone Bubbling and Ultraviolet Irradiation

Abstract

Previously, we presented the results of experiment on the decolorization of the humate solution, which is one of the persistent substances utilizing the pulsed discharge in bubbles. In this paper, we describe experimental results and discussions on the decolorization of humate solution by ozone bubbling and ultraviolet (UV) irradiation.A silent discharge type ozone generator and low pressure mercury lamps are provided in this study. Ozone concentration is varied with applied voltage across the both electrodes in the ozone generator which has a concentric cylinder electrode. Two kinds of low pressure mercury lamps of which the shortest wave length of light emission are limited at 180nm, and 200nm are prepared as UV source. The absorbance, pH and total carbon concentration in the humate solution are measured by a spectrophotometer, a pH meter and a total organic carbon analyzer. From the results, the temporal variations of absorbance and total carbon concentration in humate solution are observed after the ozone bubbling and ultraviolet irradiation. It is clarified that the variation of absorbance in humate solution by ozone bubbling is effective and UV in shorter than 200nm wavelength is remarkable to decolorize the humate solution.