摘要
采用巨正则系综的蒙特卡罗(GCMC)方法研究了CO_2在LTA型沸石上的吸附.研究表明经典力场不适合CO_2/LTA沸石吸附体系.通过拟合实验数据得到一组优化力场参数.基于优化力场的模拟结果表明:二氧化碳主要吸附在4A沸石超笼的中心和超笼中Na^+离子附近朝向中心的位置,能量分布图的相应位置也显示了较强的作用力.而对于5A沸石,由于8元环孔口处没有阳离子,二氧化碳主要吸附在八元环孔道中和八面沸石笼的中心.用优化力场计算了4A与5A沸石吸附二氧化碳的吸附热(273K),计算结果与文献值比较吻合.
Adsorptions of carbon dioxide on 4A and 5A zeolites were investigated by grand canonical Monte Carlo （GCMC） method. It is found that the classical force fields are not suitable for the system of carbon dioxide adsorption on LTA zeolite. The optimized force field parameters were obtained by titling the experimental data. The simulation results show that in 4A zeolite, the carbon dioxide molecules are mostly located in the centre of the surpercage and near the Na^＋ cations toward the centre, where the energy distribution picture also shows stronger interactive energy. Because of the existence of Na^＋ cations, there are no CO2 at the 8-member ring channel. For 5A zeolite, there are no cations at the 8- member ring channels, so the carbon dioxide can be adsorbed in the 8- member ring channels and in the centre of the surpercages. The heats of adsorption are calculated and in good agreement with the experimental data from the literatures.
出处
《计算机与应用化学》
CAS
CSCD
北大核心
2008年第6期654-658,共5页
Computers and Applied Chemistry
