DNA促进蒙脱石上多环芳烃的吸附,Environmental Science & Technology

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DNA促进蒙脱石上多环芳烃的吸附
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2018-02-21 00:00:00 , DOI: 10.1021/acs.est.7b05174
Chao Qin ₁ , Wei Zhang ₂ , Bing Yang ₁ , Xuwen Chen ₁ , Kang Xia ₃ , Yanzheng Gao ₁

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多环芳烃（PAHs）对蒙脱石的吸附在很大程度上受其与溶解有机物（DOM）的相互作用的影响。但是，鲜为人知的是，DOM对腐殖酸和腐殖酸（例如，细胞外DNA）的吸附在PAH吸附到土壤粘土中的作用尚不清楚。在这里，我们证明细胞外双链鲑鱼睾丸DNA大大增加了菲和pyr对Na-，Ca-和Fe改性蒙脱石的吸附。所有的PAH吸附等温线都很好地拟合了线性模型和Freundlich模型（R ²= 0.918–0.999）。对于菲和pyr，分配系数分别从0 mg / L DNA时的0.0458-0.103和0.0493-0.141 L / g增加到10mg / L DNA时的0.413-0.589和0.385-0.560 L / g。光谱和计算化学分析证实，PAHs首先通过范德华和π-π电子供体-受体相互作用与核碱基结合而被插入DNA。与多环芳烃相比，DNA-PAH络合物除了可嵌入粘土夹层外，还可以通过DNA磷酸酯和可交换阳离子之间的络合而更容易吸附到阳离子改性的蒙脱石上。这项工作凸显了理解控制土壤中许多普遍存在的但没有腐殖酸和富里酸的有机化合物对污染物吸附的控制的重要性。

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DNA Facilitates the Sorption of Polycyclic Aromatic Hydrocarbons on Montmorillonites

The sorption of polycyclic aromatic hydrocarbons (PAHs) to montmorillonites is largely influenced by their interactions with dissolved organic matter (DOM). However, the role of DOM rather than humic and fulvic acids (e.g., extracellular DNA) in the PAH sorption to soil clays is little known. Here, we demonstrate that extracellular double-stranded salmon testes DNA substantially increased the sorption of phenanthrene and pyrene to Na-, Ca-, and Fe-modified montmorillonites. All PAH sorption isotherms fitted the linear and Freundlich models reasonably well (R² = 0.918–0.999). Distribution coefficients were increased from 0.0458–0.103 and 0.0493–0.141 L/g at 0 mg/L DNA to 0.413–0.589 and 0.385–0.560 L/g at 10 mg/L DNA for phenanthrene and pyrene, respectively. Spectroscopic and computational chemistry analyses confirmed that PAHs were first inserted into DNA by binding with the nucleobases via van der Waals and π–π electron donor–acceptor interactions. Compared to PAHs, the DNA–PAH complex can be more easily sorbed to cation-modified montmorillonites by complexation between DNA phosphate and exchangeable cations in addition to intercalation into clay interlayers. This work highlights the importance of understanding the control on contaminant sorption by many organic compounds that are ubiquitous in soils but not represented by humic and fulvic acids.

更新日期：2018-02-22

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