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利用分子力学(molecular mechanics,MM)和分子动力学(molecular dynamics,MD)模拟了K-蒙脱石层间阳离子和水的结构及动力学特征,并将模拟的X射线衍射结果与实验值进行比较。结果显示:在K-蒙脱石的最优构型中,层间距随着水含量的增加而增大;X射线衍射的模拟结果和实验结果一致;K+的位置和蒙脱石层间电荷位置有关,K+在1,2层水合物中依附于黏土的表面附近,而在3层水合物中K+则脱离表面开始向层中其它方向扩散。水分子在黏土层间分散于各个方向,而且存在水质子和K+竞争电荷位置的现象。水和K+在钾基蒙脱石中的活动性低于其在水中和溶液中的活动性。径向分布函数分析结果表明K+组织水分子的能力有限,说明K+对蒙脱石的水化膨胀起抑制作用。
The structural and kinetic characteristics of C-K and interlayer water and K-montmorillonite were simulated by molecular mechanics (MM) and molecular dynamics (MD). The simulated X-ray diffraction results were compared with the experimental data Compare The results show that in the optimal configuration of K-montmorillonite, the interlayer spacing increases with the increase of water content. The simulation results of X-ray diffraction are consistent with the experimental results. The K + position and intergranular charge position , K + is attached to the surface of the clay in the first and second layers of hydrates, whereas in the third layer of hydrate, K + is released from the surface and begins to diffuse in the other direction of the layer. Water molecules are dispersed in all directions between clay layers, and there is a phenomenon that water protons and K + compete for the charge sites. The activity of water and K + in potassium-based smectites is lower than their activity in water and in solution. The results of radial distribution function analysis show that the ability of water molecules in K + tissue is limited, indicating that K + can inhibit the hydration swelling of montmorillonite.