Duca Clara, Imoberdorf Gustavo, Mohseni Madjid
a Department of Chemical and Biological Engineering , University of British Columbia , Vancouver , British Columbia , Canada.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2017 May 12;52(6):524-532. doi: 10.1080/10934529.2017.1282770. Epub 2017 Feb 21.
This research focused on the effects of inorganic water constituents on the efficiency of vacuum UV (VUV) for the degradation of micropollutants in surface water supplies. Atrazine was used as a model miropollutant, and bicarbonate, sulphate, and nitrate were used as the most common inorganic constituents in the water matrix. First, the absorbance of radiation at 254 and 185 nm was measured in the presence of different ions. At 254 nm, only nitrate showed a measurable absorption coefficient of [Formula: see text] = 3.51 M[Formula: see text] cm[Formula: see text], and all other ions showed a molar absorption coefficient below the detection limit. However, at 185 nm, all the ions showed high absorption coefficients, with nitrate giving the highest absorption coefficient of [Formula: see text] = 5568 M[Formula: see text] cm[Formula: see text]. Second, the hydroxyl radical (HO[Formula: see text]) scavenging effects of the same inorganic ions were evaluated; nitrate and bicarbonate showed a negative effect during the UV/HO and VUV advanced oxidation processes. Sulfate was photolyzed with 185 nm UV to form HO[Formula: see text], and for this reason, it assisted the degradation of the target micropollutant, as demonstrated by increases in the degradation rate constant. An additional component of this work involved developing a method for measuring the quantum yield of atrazine at 185 nm. This made it possible to distinguish the contribution of OH radical attach from that of direct photolysis towards the degradation of atrazine.
本研究聚焦于无机水中成分对真空紫外（VUV）降解地表水供应中微污染物效率的影响。阿特拉津被用作模型微污染物，碳酸氢盐、硫酸盐和硝酸盐被用作水基质中最常见的无机成分。首先，在不同离子存在的情况下测量了254和185nm处的辐射吸光度。在254nm处，只有硝酸盐显示出可测量的吸收系数[公式：见正文]=3.51M[公式：见正文]cm[公式：见正文]，而所有其他离子的摩尔吸收系数均低于检测限。然而，在185nm处，所有离子均显示出高吸收系数，其中硝酸盐的吸收系数最高，为[公式：见正文]=5568M[公式：见正文]cm[公式：见正文]。其次，评估了相同无机离子的羟基自由基（HO[公式：见正文]）清除效果；在紫外/羟基和真空紫外高级氧化过程中，硝酸盐和碳酸氢盐显示出负面影响。硫酸盐在185nm紫外光下光解形成HO[公式：见正文]，因此，它有助于目标微污染物的降解，降解速率常数的增加证明了这一点。这项工作的另一个部分涉及开发一种测量185nm处阿特拉津量子产率的方法。这使得区分羟基自由基附着和直接光解对阿特拉津降解的贡献成为可能。
