期刊
ENVIRONMENTAL SCIENCE & TECHNOLOGY
卷 41, 期 13, 页码 4640-4646出版社
AMER CHEMICAL SOC
DOI: 10.1021/es062529n
关键词
-
Pulse radiolysis experiments were conducted on dissolved organic matter (DOM) samples isolated as hydrophobic and hydrophilic acids and neutrals from different sources (i.e., stream, lake, wastewater treatment plant). Absolute bimolecular reaction rate constants for the reaction of hydroxyl radicals (circle OH) with DOM (k circle(OH, DOM)) were determined. k circle(OH, DOM) values are expressed as moles of carbon. Based on direct measurement of transient DOM radicals DOM circle) and competition kinetic techniques, both using pulse radiolysis, the k circle(OH, DOM) value for a standard fulvic acid from the Suwannee River purchased from the International Humic Substances Society was (1.60 +/- 0.24) x 10(8) M-1 s(-1). Both pulse radiolysis methods yielded comparable k circle(OH, DOM) values. The k circle(OH, DOM) values for the seven DOM isolates from different sources ranged from 1.39 x 10(8) M-1 s(-1) to 4.53 x 10(8) M-1 s(-1), and averaged 2.23 x 10(8) M-1 s(-1) (equivalent to 1.9 x 10(4)(mgC/L)(-1) s(-1)). These values represent the first direct measurements of k circle(OH, DOM), and they compare well with literature values obtained via competition kinetic techniques during ozone or ultraviolet irradiation experiments. More polar, lower-molecular-weight DOM isolates from wastewater have higher k circle(OH, DOM) values. In addition, the formation (microsecond time scale) and decay (millisecond time scale) of DOM circle transients were observed for the first time. DOM circle from hydrophobic acids exhibited broader absorbance spectra than transphilic acids, while wastewater DOM isolates had narrower DOM circle spectra more skewed toward shorter wavelengths than did DOM circle spectra for hydrophobic acids.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据