苯分子与Si6O18H12和Al6O24H30团簇模型相互作用的理论研究

粘土矿已经被广泛用来去除有机物，修复和净化被石油碳氢化合物污染的土壤和地下水. 我们选择高岭石作为研究对象，构造了Si₆O₁₈H₁₂和Al₆O₂₄H₃₀两个团簇模型分别代表高岭石的硅氧层表面和铝氧层表面，在MP2/6-31G(d，p)//B3LYP/6-31G(d，p)的理论水平上系统地研究了气态下苯分子和高岭石团簇模型的相互作用. 并进一步分析了苯分子和高岭石表面相互作用的各种气态性质，比如：优化的几何构型、结构参数、吸附能、自然键轨道电荷分布、振动频率变化、静电势、电子密度性质(次级氢键的电子密度和拉普拉斯算符值)和电子密度差分等. 优化的几何构型表明苯分子吸附在高岭石表面的本质可能是次级氢键的形成. 其他性质的结果进一步验证了次级氢键的存在，并指出苯更倾向于吸附在高岭石的铝氧层表面，且苯环和铝氧层表面形成近似90°的夹角.

Theoretical Investigation of Interaction of Benzene Molecule and Si6O18H12 and Al6O24H30 Cluster Models

Clay minerals are used to remove organics and to remediate soils and groundwater contaminated with petroleum hydrocarbons. Cluster models of Si₆O₁₈H₁₂ and Al₆O₂₄H₃₀ for the tetrahedral (Si―O) and octahedral (Al―O) surfaces of kaolinite were set up to mimic kaolinite surfaces. The interactions of benzene molecule and the kaolinite cluster models were systematically studied at the MP2/6- 31G(d,p)//B3LYP/6-31G(d,p) level. The gas- state adsorption properties of benzene on the kaolinite surfaces, such as the optimized structures, structural parameters, adsorption energies, natural bond orbital charge distributions, vibration frequencies, electrostatic potential maps, electron density characteristics (the ρ and ▽²ρ values of secondary hydrogen-bonds), and electron density difference, were analyzed in this work. The optimized structures indicate that the adsorption of benzene molecule on the kaolinite surfaces may be caused by formation of secondary hydrogen-bonds. The results for the other properties further confirmed the existence of secondary hydrogen-bonds. Benzene molecule is more likely to be adsorbed on the Al―O surface than on the Si―O surface. The adsorption angle between the benzene ring plane and the kaolinite Al―O surface is about 90°.