| 摘要: |
| 我国南方桉树林区水库秋冬季黑水频发,桉树叶中单宁酸等物质与金属离子如铁离子产生的络合物是主因。但目前对于桉树叶浸泡液分子组成与水库黑水的关联机制还尚不清楚。本研究利用傅立叶变换离子回旋共振质谱(FT-ICR MS)等手段,对桉树叶浸泡液与典型桉树林区水库(金窝水库和天雹水库)水体中可溶性有机物进行分子组成的分析。研究结果表明,桉树叶浸泡液主要由一些以苯三酚、没食子酸为母体的多酚类化合物及其多聚衍生物组成,其中最典型化合物为鞣花酸(C14H6O8)。这些芳香多酚类物质易与金属离子如铁离子发生络合反应生成黑色沉淀,是水库变黑的核心因素。冬季水库水中鞣花酸强度远高于夏季,且表层水体高于底层水体,这表明秋冬季大量凋落的桉树叶释放的这些芳香多酚类物质会显著促进水库黑水的形成。金属-有机质络合物是水体中重要的化学组成,影响无机金属离子在液固两相中的分配。本研究为水体中形成金属-有机质络合物的潜在有机质前体物提供重要证据。 |
| 关键词: 桉树 黑水 芳香多酚类物质 鞣花酸 金属-有机质络合物 傅立叶变换离子回旋共振质谱 |
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| 基金项目:广西重点研发计划项目（桂科AB20297017）和广州市2023年度基础与应用基础项目（SL2022A04J00209）联合资助。 |
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| Molecular composition and formation mechanism of black matter in water body of Eucalyptus artificial forest area in southern China |
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Li mingjie,Jiang bin,Guo jinchuan,Pan yue,Jiang ran,Liao yuhong,Zhu xinhai,Chen zilong
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Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou , China
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| Abstract: |
| Black water frequently occurs in the reservoirs of eucalyptus forest region in southern China in autumn and winter. Tannic acid and other substances in eucalyptus leaves and metal ions such as iron ions are the main causes. However, the correlation mechanism between the molecular composition of eucalyptus leaf soaking solution and reservoir black water is still unclear. In this study, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and other methods were used to analyze the molecular composition of soluble organic matter in the soaking solution of eucalyptus leaves and the water body of typical eucalyptus forest reservoirs (Jinwo Reservoir and Tianbao Reservoir). The results showed that the soaking solution of eucalyptus leaves was mainly composed of some polyphenolic compounds and their polymerized derivatives with pyrogallol and gallic acid as the parent, among which the most typical compound was ellagic acid (C14H6O8). These aromatic polyphenols are easy to react with metal ions such as iron ions to form black precipitate, which is the core factor of reservoir blackening. The intensity of ellagic acid in the reservoir water in winter is much higher than that in summer, and the surface water is higher than the bottom water, which indicates that these aromatic polyphenols released by the large number of fallen eucalyptus leaves in autumn and winter will significantly promote the formation of black water in the reservoir. Metal-organic complex is an important chemical composition in water, which affects the distribution of inorganic metal ions in liquid-solid phase. This study provides important evidence for the formation of potential organic precursors of metal-organic complexes in water. |
| Key words: Eucalyptus black water aromatic polyphenols ellagic acid metal-organic complex FT-ICR MS |
