Spectroscopic techniques for quantitative characterization of Cu (II) and Hg (II) complexation by dissolved organic matter from lake sediment in arid and semi-arid region.
Spectroscopic techniques for quantitative characterization of Cu (II) and Hg (II) complexation by dissolved organic matter from lake sediment in arid and semi-arid region.
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DOI：
10.1016/j.ecoenv.2012.08.016
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发表时间：
2012-11
影响因子：
6.8
通讯作者：
Xu Guo;Dong-hai Yuan;Qiang Li;Jin-yuan Jiang;Feng-Xian Chen;Hui Zhang
中科院分区：
文献类型：
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作者：
Xu Guo;Dong-hai Yuan;Qiang Li;Jin-yuan Jiang;Feng-Xian Chen;Hui Zhang
提取了干旱半干旱地区6个沉积物样品中的溶解有机质（DOM），并利用荧光激发发射矩阵（EEMs）对其进行了表征。结果表明，湖泊沉积物DOM中存在4个类富里酸荧光峰（A峰）、类胡敏酸荧光峰（C峰）和2个类胡敏酸荧光峰（B和D峰）。荧光猝灭滴定表明，添加Cu（II）和Hg（II）后，B和D峰逐渐被猝灭，而类腐殖酸物质的荧光强度变化没有系统的趋势。利用修正的Stern-Volmer模型计算了条件稳定常数（logK）和参与DOM与Cu（II）、Hg（II）络合作用的荧光团百分比（f %）。结果表明，DOM-Cu（II）和DOM-Hg（II）配合物具有较高的logK值（4.21-5.23），DOM-Cu（II）的logK值远大于Hg（II）的相应值。峰B显示出比峰D相对低的logK和高的f %值。不同污染源（主要来自上游工业废水、生活污水和农田灌溉回水）对Cu（II）和Hg（II）的稳定常数和络合容量均有影响。
Dissolved organic matter (DOM) was extracted from six sediment samples in arid and semi-arid region, which was characterized by fluorescence excitation–emission matrices (EEMs). The results showed that four fluorescent peak, fulvic-like (peak A), humic-like (peak C) and two tryptophan-like (peaks B and D), were identified in lake sediment DOM. Fluorescence quenching titration showed that peaks B and D were quenched gradually by adding additional Cu (II) and Hg (II), whereas humic-like substances had no systematic trend of the change of fluorescence intensity. Increasing fluorescence intensity value of humic-like substances can also be found. The modified Stern–Volmer model was used to calculate conditional stability constants (logK) and the percent of fluorophores (f %) which participate in the complexation between DOM and Cu (II), and Hg (II). The results showed that DOM-Cu (II) and DOM-Hg (II) complexes had higher logK values of 4.21–5.23 and the logK values of DOM-Cu (II) are much larger than the corresponding values for Hg (II). Peak B showed relatively low logK and high f % values than those of peak D. Different pollution sources which are mainly obtained from the upstream industrial wastewater, domestic sewage and return water of farmland irrigation tend to affect the stability constants and complexing capacities of Cu (II) and Hg (II).