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International Journal of Photoenergy
Volume 2012, Article ID 107293, 10 pages
http://dx.doi.org/10.1155/2012/107293
Research Article

Bromate Formation Characteristics of UV Irradiation, Hydrogen Peroxide Addition, Ozonation, and Their Combination Processes

1Faculty of Science and Technology, Ryukoku University, 1-5 Yokotani, Setaoe-cho, Otsu 520-2194, Japan
2Graduate School of Science and Technology, Ryukoku University, 1-5 Yokotani, Setaoe-cho, Otsu 520-2194, Japan

Received 28 May 2012; Revised 8 August 2012; Accepted 8 August 2012

Academic Editor: Manickavachagam Muruganandham

Copyright © 2012 Naoyuki Kishimoto and Eri Nakamura. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Bromate formation characteristics of six-physicochemical oxidation processes, UV irradiation, single addition of hydrogen peroxide, ozonation, UV irradiation with hydrogen peroxide addition (UV/H2O2), ozonation with hydrogen peroxide addition (O3/H2O2), and ozonation with UV irradiation (O3/UV) were investigated using 1.88 μM of potassium bromide solution with or without 6.4 μM of 4-chlorobenzoic acid. Bromate was not detected during UV irradiation, single addition of H2O2, and UV/H2O2, whereas ozone-based treatments produced . Hydroxyl radicals played more important role in bromate formation than molecular ozone. Acidification and addition of radical scavengers such as 4-chlorobenzoic acid were effective in inhibiting bromate formation during the ozone-based treatments because of inhibition of hydroxyl radical generation and consumption of hydroxyl radicals, respectively. The H2O2 addition was unable to decompose 4-chlorobenzoic acid, though O3/UV and O3/H2O2 showed the rapid degradation, and UV irradiation and UV/H2O2 showed the slow degradation. Consequently, if the concentration of organic contaminants is low, the UV irradiation and/or UV/H2O2 are applicable to organic contaminants removal without bromate formation. However, if the concentration of organic contaminants is high, O3/H2O2 and O3/UV should be discussed as advanced oxidation processes because of their high organic removal efficiency and low bromate formation potential at the optimum condition.