College of Resources and Environment, Northwest A & F University, Yangling 712100, China.
College of Resources and Environment, Northwest A & F University, Yangling 712100, China; Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China.
Sci Total Environ. 2021 Sep 10;786:147493. doi: 10.1016/j.scitotenv.2021.147493. Epub 2021 May 3.
The researches on transformation of polycyclic aromatic hydrocarbons (PAHs) on clay minerals modified by metal ions have received increasing attention. However, the transformation of PAHs with electron-withdrawing or electron-donating substitutional groups on clay minerals is not well understood currently. In this study, the degradation of anthracene (ANT) with different substituents (including -CH, -CHO, -Br, -OMe, and -NO) on Al(III)-montmorillonite (MMT) was investigated in the dark. The results showed that aromatic compounds were degraded with the rate constants (k) of 0.004-0.141 d. Moreover, ANT with electron-donating substituents (e.g., -CH, -OMe) had a higher transformation rate than that with electron-withdrawing substituents (e.g., -Br, -NO). The reactive oxygen species (ROS) quenching experiments indicated that ROS played a significant role in the transformation of ANT and ANT derivatives. Density functional theory (DFT) calculations revealed that the reactivity of single substituted PAHs was highly correlated with their ionization potential (IP), the energy of highest occupied molecular orbital (E), the energy of lowest unoccupied molecular orbital (E), and electronegativity (ζ), while independent of hardness (η). This study provides novel insights into predicting the reactivity of PAHs derivatives, and lays a fundamental basis for better understanding the fate of substituted PAHs in soils.
金属离子改性粘土矿物上多环芳烃（PAHs）转化的研究受到了越来越多的关注。然而，目前对于带有吸电子或供电子取代基的 PAHs 在粘土矿物上的转化还了解甚少。在这项研究中，在黑暗条件下研究了 Al(III)-蒙脱石（MMT）上带有不同取代基（包括-CH、-CHO、-Br、-OMe 和 -NO）的蒽（ANT）的降解。结果表明，芳香族化合物的降解速率常数（k）为 0.004-0.141 d。此外，带有供电子取代基（如-CH、-OMe）的 ANT 比带有吸电子取代基（如 -Br、-NO）的 ANT 具有更高的转化速率。活性氧物种（ROS）猝灭实验表明，ROS 在 ANT 和 ANT 衍生物的转化中起着重要作用。密度泛函理论（DFT）计算表明，单取代 PAHs 的反应活性与它们的电离势（IP）、最高占据分子轨道（E）的能量、最低未占据分子轨道（E）的能量和电负性（ζ）高度相关，而与硬度（η）无关。这项研究为预测 PAHs 衍生物的反应活性提供了新的见解，并为更好地理解取代 PAHs 在土壤中的命运奠定了基础。
