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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.
The adsorption of CO_2 on LTA zeolites was studied by Monte Carlo method of giant canonical ensemble (GCMC). The results show that the classical force field is not suitable for CO_2 / LTA zeolite adsorption system. By fitting the experimental data, a set of optimized force field parameters The simulation results based on the optimized force field show that carbon dioxide is mainly adsorbed on the center of 4A supercages and Na + ions in the supercages towards the center, and the corresponding position of the energy distribution map also shows a strong force. For 5A zeolite, the main adsorption of carbon dioxide is in the center of the octahedral ring channel and octahedral zeolite cage due to the absence of cations at the 8-ring orifice.The adsorption heat (273K) of carbon dioxide adsorbed by 4A and 5A zeolites is calculated by the optimized force field, The calculated results are in good agreement with the literature values.