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Assessment of 265-nm UV-LED for direct photolysis and advanced oxidation of N-nitrosamines and 1,4-dioxane

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Title: Assessment of 265-nm UV-LED for direct photolysis and advanced oxidation of N-nitrosamines and 1,4-dioxane
Authors: Fujioka, Takahiro / Kodamatani, Hitoshi / Yoshikawa, Takumi / Inoue, Daisuke / Ikehata, Keisuke
Issue Date: 9-Sep-2020
Publisher: Elsevier B.V.
Citation: Environmental Technology and Innovation, 20, art.no.101147; 2020
Abstract: The advanced oxidation process (AOP), using conventional low-pressure mercury (LP Hg)-vapor UV lamps, forms a critical barrier for pathogens and contaminants of emerging concern (CECs) in potable water reuse. In recent years, UV-light-emitting diode (UV-LED) has attracted considerable attention as an alternative UV source because it has a long lifetime and is mercury-free. This study assesses the effectiveness of 265-nm UV-LED in removal of characteristic CECs, 1,4-dioxane (100 μg/L) and N-nitrosamines (500 ng/L), including N-nitrosodimethylamine (NDMA), in recycled potable water. Direct photolysis using a UV-LED lamp, at the maximum UV dose of 900 mJ/cm2, achieved a maximum of 31% NDMA reduction, as opposed to a 93% reduction by a conventional LP Hg UV lamp. We attributed this to the longer emission wavelength of the UV-LED (265 nm) than that for the LP Hg UV lamp (254 nm). Both UV lamps failed to photolyze 1,4-dioxane. Using hydrogen peroxide or monochloramine remarkably enhanced the effectiveness of the LP Hg UV-based AOP in removing 1,4-dioxane, and the percentage of NDMA removed also increased slightly; however, it did not improve the effectiveness of the UV-LED-based AOP. We conclude from this study that despite the advantages of the UV-LED over the conventional LP Hg UV lamp, the former performs ineffectively at attenuating major CECs in recycled water.
Keywords: 1,4-dioxane / Advanced oxidation process / CECs / NDMA / Potable reuse / UV-LED
URI: http://hdl.handle.net/10069/40326
ISSN: 23521864
DOI: 10.1016/j.eti.2020.101147
Rights: © 2020 Elsevier B.V. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Type: Journal Article
Text Version: publisher
Appears in Collections:Articles in academic journal

Citable URI : http://hdl.handle.net/10069/40326

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