CO_2、CH_4在改性MFI沸石中吸附的分子模拟

Molecular simulation of CO_2,CH_4 adsorption in modified MFI zeolites

采用巨正则蒙特卡洛(GCMC)方法研究了CO2、CH4在全硅MFI沸石和MFI(4Na+)沸石中的吸附行为,计算获得了CO2、CH4在两种架构中的吸附等温线、吸附能量分布曲线和粒子云分布图,结果表明:CO2、CH4纯组分在较低压力下有较高的吸附量,并且吸附量随压力的增大而增加,随温度的升高而小幅减少,其混合组分在两架构中均发生明显的竞争吸附行为;Na+的存在使MFI型沸石对CO2的吸附能力和选择性得到增强。

The adsorption behaviors of CO2,CH4 in all-silica MFI and MFI（4Na＋） zeolites are stu-died using Grand Canonical Monte Carlo method（GCMC）.Isotherms of different temperatures for pure component and binary mixtures are obtained.Adsorption isotherms,adsorption energies distributions and mass clouds distributions of CO2,CH4 in two structures are obtained.The results show that the adsorption amount of pure component is higher at low pressure,the amount increases with the increase of pressure and decreases slightly with the increase of temperature,and the binary mixtures show evident competitive adsorption behavior.The presence of Na＋ enhanced the adsorption ability and selectivity of CO2 in MFI zeolites.