采用巨正则蒙特卡罗(GCMC)和平衡分子动力学(EMD)方法,模拟乙二醇(EG)/水在NaA分子筛孔道中的吸附与扩散行为。结果表明:混合组分间存在着显著的竞争吸附行为,水的吸附量随水质量分数的升高呈增大趋势,与实验中渗透通量的变化趋势相吻合;纯水的扩散速率明显高于乙二醇的扩散速率,混合组分的扩散行为受分子间互相作用影响显著,乙二醇分子对水分子的扩散产生显著的阻滞作用,从而影响了NaA分子筛膜的渗透通量。
Behaviors of adsorption and diffusion for ethylene glycol( EG) /water in NaA zeolite were simulated by grand canonical ensemble Monte Carlo( GCMC) and equilibrium molecular dynamics( EMD) methods,respectively. Results showed that strong competitive adsorption behavior existed in NaA zeolite for EG / water mixture. Water loading increased with water content of feed,it was in agreement with the trend of permeation flux for pervaporation dehydration. The diffusivity of pure water molecules was greater than that of pure EG. Furthermore,the diffusion behavior of EG / water mixture through NaA zeolite membrane was prominently affected by the interaction between the two components. The EG molecules could slow down diffusion of water molecules significantly,thus it would affect permeation flux of NaA zeolite membrane.