高岭石层间尿素-水体系的分子动力学模拟

用分子动力学（MD）方法对尿素-高岭石和尿素-水-高岭石两个体系进行模拟,计算结果表明，在300K时,高岭石平衡层间距随着尿素分子的增多不断增大,增幅逐渐减小;尿素在水溶液中的摩尔分率在0.58左右时高岭石平衡层间距有最大值。尿素在高岭石片层间成双层分布,分别通过O=C键和N—H键与高岭石表面原子形成氢键。水在层间主体相成三层分布,有部分水分子吸附在高岭石表面上。

Molecular dynamics simulation of the intercalation of kaolinite with urea and water

The intercalation of kaolinite with urea-water mixtures has been studied by molecular dynamics simulations. The results at 300 K show that the basal distance increases with the increasing number of urea molecules and that the system has the maximum basal distance when the mole fraction of urea in the mixture is 0.58. The urea molecules are divided into two layers in the kaolinite: one layer interacts with the surfaces of kaolinite by hydrogen bonding through O=C bonds, and the other interacts by hydrogen bonding via N—H bonds. The water olecules are divided into three layers in the kaolinite, with a small umber of water molecules adsorbed on the surface of the material.