水分子在白云母表面吸附的分子动力学模拟

作为一种重要的化工分离技术,浮选过程中的固/液界面现象极为重要.利用PCFF_phyllosilicates力场对不同数量的水分子在白云母表面的吸附情况进行了分子动力学研究,考察了原子密度分布、氢键相对浓度分布、径向分布函数、均方位移和表面K⁺密度场等性质.结果表明:水分子达到单层覆盖后,靠近白云母(001)表面的前3层水分子的数目不随水分子的进一步增多发生改变;界面处的水分子比远离表面的水分子排列更为有序;原子密度分布、氢键相对浓度分布结果详细反映了白云母基质对水分子微观影响的"固体效应".研究还表明,表面K⁺在水化条件下移动性差,尤其是z方向流动性最差,K⁺密度场图也证明[Si₄Al₂]^-K⁺结构非常稳定.

Molecular dynamics simulation of water molecules adsorbed at muscovite (001) surface

As an important separation technique, microscopic phenomena of solid/liquid interface are crucial in flotation process. A molecular dynamics simulation is performed with PCFF_phyllosilicates force field to study the adsorption of water molecules on the muscovite surface, and atomic density profiles, hydrogen bond profiles, radical distribution function, mean squared displacement and density field are calculated. Results show that at a surface with water coverage larger than 1, the number of water molecules in the first three layers near the muscovite (001) surface will be stable with the increase of water molecules; water molecules closed to the surface represent much more ordering than those far from the surface; "solid effect" in the microscopic phenomena in the water solution is stressed by change trends of atomic density profiles and hydrogen bond profiles. It is found that K⁺ have poor mobility, especially in the z direction, and the stability of [Si₄Al₂]^-K⁺ structure is proven via the density field of K⁺.