Environmental pH and ionic strength influence the electron-transfer capacity of dissolved organic matter
Environmental pH and ionic strength influence the electron-transfer capacity of dissolved organic matter
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DOI：
10.1007/s11368-015-1154-y
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发表时间：
2015-05
影响因子：
3.6
通讯作者：
Qin Lu;Yong Yuan;Yaxin Tao;Jia Tang
中科院分区：
文献类型：
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作者：
Qin Lu;Yong Yuan;Yaxin Tao;Jia Tang
目的溶解有机物(DOM)因其电子传递能力(ETC)而在环境中的元素循环和污染物转化中发挥着重要作用，但ETC可能受到pH和离子强度等环境因素的影响。本研究旨在揭示 pH 值和离子强度对 DOM 的 ETC 的影响及其可能的机制。 材料和方法将 DOM 制备成不同 pH 值（4、6、7、8 和 10）和离子强度（0.001、0.01、0.1 和 0.5 mol/L KCl）的溶液。采用计时电流法测定 DOM 的 ETC，包括受电子能力 (EAC) 和供电子能力 (EDC)。通过评估 DOM 的光谱和色谱性质，获得相关的结构信息，探讨 ETC 变化的可能机制。结果与讨论随着 pH 从 4 增加到 10，DOM 的 EAC 和 EDC 持续增加。EAC 和 EDC 随着离子强度的增加而增加，在 0.1 mol/L KCl 时达到峰值，然后下降。凝胶渗透色谱图显示不同pH和离子强度溶液中DOM的分子尺寸分布不同。结论环境pH和离子强度通过改变DOM分子的构象影响DOM的ETC。
PurposeDissolved organic matter (DOM) plays an important role in the cycling of elements and the transformation of pollutants in the environment due to its electron-transfer capacity (ETC), but ETC may be affected by environmental factors such as pH and ionic strength. This study was aimed to reveal the effects of pH and ionic strength on the ETC of DOM and the possible mechanisms.Materials and methodsDOM was prepared into solutions with various pH values (4, 6, 7, 8, and 10) and ionic strength (0.001, 0.01, 0.1, and 0.5 mol/L KCl). ETC of DOM including electron-accepting capacity (EAC) and electron-donating capacity (EDC) was determined with chronoamperometry. Spectroscopic and chromatographic properties of DOM were evaluated to obtain related structural information to explore the possible mechanisms for the ETC changes.Results and discussionBoth the EAC and EDC of DOM increased consistently with increasing pH from 4 to 10. EAC and EDC increased with increasing ionic strength, peaked at 0.1 mol/L KCl, and then decreased. Gel permeation chromatogram displayed different molecular size distribution for the DOM in solution with different pH and ionic strength.ConclusionsEnvironmental pH and ionic strength influence the ETC of DOM by altering the conformation of DOM molecules.