正己烷在不同硅铝比HZSM-5分子筛上吸附的分子模拟研究

采用巨正则蒙特卡洛方法研究了正己烷在不同硅铝比的HZSM-5分子筛上的吸附行为。通过模拟298 K和423 K下正己烷分子在不同硅铝比的HZSM-5分子筛上的吸附，得到并分析了其吸附等温线、吸附能量密度图、吸附势能、径向分布函数等相关参数，重点分析了硅铝比对正己烷分子吸附行为的影响。结果表明：正己烷与HZSM-5分子筛间的吸附符合Langmuir-Freundlich吸附模型；高硅铝比时，正己烷分子优先吸附在HZSM-5分子筛交叉孔道中T₃和T₉位的B酸位上，且正己烷分子间的相互作用较明显；随着硅铝比的降低，正己烷的饱和吸附量升高，在直孔道吸附的正己烷分子比例增加，正己烷分子间的相互作用减弱。

MOLECULAR SIMULATION OF n-HEXANE ADSORPTION ON HZSM-5 ZEOLITES WITH DIFFERENT Si Al RATIO

The adsorption behavior of n-hexane on HZSM-5 zeolites with different Si/Al ratios has been simulated by Grand Cannonical Monte Carlo method. By simulating the adsorption of n-hexane molecules on HZSM-5 zeolites with different Si-Al ratios at 298 K and 423 K, some parameters such as the adsorption isotherm, adsorption energy density, adsorption potential energy, radial distribution function and other related parameters were obtained and analyzed, and the effect of Si/Al ratio on the adsorption behavior of n-hexane was also analyzed. The results show that the adsorption between n-hexane and HZSM-5 zeolite accords with the Langmuir-Freundlich adsorption model. When the Si/Al ratio is high, n-hexane molecules adsorbs preferentially on B acid sites of T3 and T9 in the inter channels of HZM-5 zeolites and the interaction between n-hexane molecules is more obvious than other B acid sites. With the decrease of Si/Al ratio, the saturated adsorption capacity of n-hexane was increased, the adsorption ratio of n-hexane molecules adsorbed in the straight channel was increased, and the interaction between hexane molecules was weaken.