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应用密度泛函理论在分子水平上研究了水在褐煤表面的微观吸附机理,在B3LYP/6-311G+(d,p)优化基础上,采用Gaussian09软件程序包计算得到褐煤表面构型及其不同煤水吸附构型,采用完全均衡校正法对其相互作用能校正重叠误差.运用Multiwfn程序和VMD软件,应用静电势分布图、散点图和约化密度梯度(RDG)填色等值图对不同褐煤表面模型进行图形化分析.结果表明:褐煤表面对水分子的吸附为物理吸附,属于弱相互作用,这些弱相互作用力以氢键作用为主,其余为范德华弱相互作用;羟基、羧基对水的吸附性最强,其他含氧基团(如醚键、甲氧基等)次之,苯环最弱;水分子吸附形成的相互作用区域并不简单地集中于某个基团或某个原子,而是与褐煤局部区域都形成一定的相互作用,这不仅增强了水分子的吸附作用,而且对褐煤结构产生较大影响.
The density functional theory was used to study the microscopic adsorption mechanism of water on the surface of lignite at the molecular level. Based on the B3LYP / 6-311G + (d, p) optimization, the surface configuration of lignite and its different coal Water adsorption configuration, the complete equilibrium calibration method can be used to correct the overlay error for its interaction.Using Multiwfn program and VMD software, electrostatic potential distribution map, scattergram and RDG fill contour map are used to simulate different lignite The results showed that the adsorption of water molecules on the surface of lignite was physical adsorption, belonging to the weak interaction, the weak interaction was dominated by hydrogen bond and the rest was van der Waals weak interaction. The hydroxyl, carboxyl on water Is the most adsorptive, the other oxygen-containing groups (such as ether bond, methoxy, etc.) followed by the weakest benzene ring; water molecules adsorbed to form the interaction of the region does not simply focus on a group or a Atoms, but some interaction with the local area of lignite, which not only enhances the adsorption of water molecules, but also has a greater impact on the structure of lignite.