摘要
用美国Micromeritics公司生产的ASAP2 0 10物理吸附仪测定了低温 (77K)N2 在MCM 41分子筛中的吸附等温线 ,获得了表征MCM 41特征的BET比表面、BJH孔容和平均孔径 .同时用巨正则MonteCarlo (GCMC)模拟方法考察了N2 在MCM 41中的吸附 ,得到了N2 在MCM 41中的模拟吸附等温线 ,分析了流体在MCM 41分子筛中的微观结构 .GCMC模拟中MCM 41介孔材料模型化为圆柱孔 ,N2 模型化为Lennard Jones (LJ)球 .N2 和MCM 41介孔墙壁间的相互作用采用Tjatjopoulos Feke Mann (TFM)势能模型进行表征 .通过使模拟和实验结果有一个好的吻合 ,确定了一组有效的MCM 41分子筛的势能参数 (σww=0 2 6 5nm ,εww/k =190K) .这为以后其他吸附质在MCM 41中吸附的预测奠定了基础。
Adsorption isotherm of nitrogen in MCM-41 at temperature T=77 K was measured by using the ASAP 2010 volumetric adsorption analyzer produced by Micromeritics Instrument Corp.. The BET specific surface was obtained. Based on the BJH analysis method, which is a suitable method for analyzing adsorption of fluid in meso-porous materials, the BJH adsorption cumulative pore volume and average pore diameter were also solved. The grant canonical Monte Carlo (GCMC) simulation was also carried out to investigate the adsorption of nitrogen in MCM-41 at T=77 K. In our GCMC simulation, the MCM-41 material was modeled as cylindrical pore, and nitrogen was considered as the Lennard-Jones spherical molecule. The Tjatjopoulos-Feke-Marin (TFM) potential was used for representing the interaction between nitrogen molecules and cylindrical pore walls. In the simulation, the diameter size was taken from the result measured. Simulated adsorption isotherm of nitrogen in MCM-41 was obtained, and the micro-structure of the fluid in MCM-41 was also analyzed, which is good guidance to understand the mechanism of adsorption. Note that a set of parameters representing MCM-41 was determined by making the experiment isotherm and simulation isotherm in a good agreement, which is a basis for predicting the adsorption of other adsorbate in MCM-41.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2002年第5期820-824,共5页
Acta Chimica Sinica
基金
国家重点基础研究发展规划项目基金 (No.G2 0 0 0 0 480 10 )
国家自然科学基金 (No.2 9776 0 4)
国家高性能计算基金 (No .99118)
教育部科学技术研究重大项目
北京市新星计划 ( 95 5 810 35 0 0 )资助项目
