环境条件对渗滤液中溶解性有机物分子构型的影响
Influence of environmental factors on the molecular conformation of dissolved organic matters extracted from landfill leachates
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摘要: 采用同步荧光光谱，结合移动窗口二维相关光谱技术，研究了垃圾渗滤液中溶解性有机物（DOM）在外界干扰下的分子构型变化.结果显示，填埋垃圾渗滤液DOM含有类蛋白、类富里酸和类胡敏酸物质，它们均含有羧基和酚羟基官能团，填埋3-5年垃圾渗滤液DOM酚羟基含量较高，且主要分布在类蛋白组分上，而填埋10年以上渗滤液DOM中羧基含量较高，但主要分布在类富里酸组分上.pH升高引起DOM分子构型改变不受Hg（Ⅱ）存在的影响，填埋3-5年垃圾渗滤液DOM在pH 3和pH 8-10时分别由于羧基和酚羟基解离分子构型发生了剧烈改变，而填埋10年以上垃圾渗滤液DOM仅在pH 3-4时由于羧基解离分子构型发生了变化.在Hg（Ⅱ）对DOM分子构型的影响上，填埋3-5年垃圾渗滤液DOM分子构型在溶液Hg（Ⅱ）浓度升至5 mmol·L-1和20-25 mmol·L-1时发生了两次剧烈改变，而填埋10年以上垃圾渗滤液DOM在体系Hg（Ⅱ）浓度为10-25 mmol·L-1发生了一次缓慢的改变.同步荧光光谱结合移动窗口二维相关光谱技术可以有效识别环境条件改变时DOM分子构型的变化及成因.
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关键词:
- 垃圾渗滤液 /
- 溶解性有机物 /
- 汞 /
- 同步荧光光谱 /
- 移动窗口二维相关光谱技术
Abstract: Synchronous fluorescence spectroscopy combined with perturbation-correlation moving-window two-dimensional correlation technique were applied to investigate the variation of molecular conformation of dissolved organic matters (DOM) extracted from landfill leachates under environment perturbation. The results showed that the landfill leachate-derived DOM comprised protein-, fulvic-and humic-like matter, which were composed of carboxyl and phenolic hydroxyl groups. The DOM from the leachates with 3-5 years comprised more phenolic hydroxyl groups, and these phenolic hydroxyl groups were mainly located in protein-like matter. On the contrary, the DOM from the leachates with > 10 years comprised more carboxyl groups, and these carboxyl groups were mainly on fulvic-like matter. The molecular conformation variation under the pH perturbation showed no correlation with the existence of Hg(Ⅱ). As for the DOM from the leachates with 3-5 years, the molecular conformation of protein-, fulvic-and humic-like fractions all changed at the pH value of 3 and 8-10 due to the dissociation of carboxyl and phenolic hydroxyl groups. Compared to that of the DOM from the leachates with 3-5 years, the molecular conformation of DOM from the old leachate showed a dramatic variation at the pH of 3-4 due to the dissociation of carboxyl groups. As for the Hg(Ⅱ) perturbation, the molecular conformation of the DOM from the leachates with 3-5 years both changed when the Hg(Ⅱ) concentrations were 5 and 20-25 μmol·L-1, respectively. On the other hand, the molecular conformation of the DOM from the leachates with > 10 years old varied when the Hg(Ⅱ) concentrations ranged from 10 to 25 μmol·L-1. Synchronous fluorescence spectroscopy combined with perturbation-correlation moving-window two-dimensional correlation technique can identify the molecular conformational variation of DOM under environmental perturbations and the causes. -
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