甲烷在中孔分子筛MCM-41中吸附的计算机模拟

采用巨正则系综Monte Carlo方法研究了甲烷在两个不同孔径的MCM-41中不同温度下的吸附等温线和其在孔中的相行为和排列方式.模拟结果显示,在较小孔径的MCM-41中,流体分子达到毛细凝聚所需的化学位较小,并且观察到两个孔径下计算机模拟得到的亚稳态区域都非常宽,使得层状转变（如果有的话）被包含在这个区域.通过比较两种孔径下达到毛细凝聚后的构型,可以看出,在3.5 nm的孔中流体的分子结构出现非常有序的排列,而在5.0 nm的孔中则没有.在常温300 K时甲烷的吸附的计算机模拟表明,孔壁对流体分子的作用仅仅影响较靠近壁面附近的流体分子的排列,而对孔中间的分子几乎没有影响.

Molecular Simulation on Adsorption of Methane in Mesopore MCM-41

Using grand canonical ensemble Mont e Carlo method,adsorption isotherm s,phase transition behav-iors and structures of methane adsor bed in two pores of MCM-41,with 3.5an d 5.0nm diameters,at 74.05K and300K have been simulated.It is found that capillary condensation occurs at a lower chemical potential for the smaller MCM-41at 74.05K,compared t hat with the pore of 5.0nm.For the two pore sizes in this study,hys-teresis loops of capillary condensa tions are so wide that layering transitions are found within them.In the t wo MCM-41pores at 74.05K,a highly ordered structure for methane molecules in 3.5nm pores is observed,in contrast to less ordered arrangemen t of the molecules for the 5.0nm pore.When the temperature is increased to300K,only methane molecules near th e walls of MCM-41are arranged in order,while the molecules near the centers of pores are arranged almost randomly.