ITQ-3分子筛中二元混合分子扩散性质的模拟  

Molecular Dynamics Simulation on Diffusion Properties of the Binary Components in Zeolite ITQ-3

作　　者：王丹丹[1] 高亚[1] 杨晓峰[1] 

机构地区：[1]中北大学理学院,太原030051

出　　处：《化学通报》2016年第3期268-271,共4页Chemistry

摘　　要：采用平衡分子动力学方法先是模拟研究了纯组分Ar、SF_6以及CF4在ITQ-3分子筛中的扩散行为,结果表明,在窄孔道中Ar的扩散系数随负载的增加呈现先增加再减小的变化趋势,在宽孔道中则随负载逐渐减小。纯组分的大分子SF_6以及CF4只在y方向扩散,扩散系数与小分子在z方向的变化规律一致。随后,又模拟了二元混合组分SF_6和CF4在ITQ-3分子筛中的扩散行为,模拟结果与各自纯组分SF_6和CF4进行了对比,发现二元混合的SF_6和CF4整体变化趋势与其单组分保持一致,在y方向的扩散系数都是随着负载的增加而先增大后减小,但是两者之间还存在一种相互作用,使得在整个负载范围内扩散较快的CF4的扩散系数比纯组分的扩散系数相对小一些,而纯组分时扩散相对缓慢的SF_6在二元混合中的扩散系数则相对增大。The equilibrium molecular dynamic simulation was carried out to study the diffusion behavior of pure component and the binary components in zeolite ITQ-3. For pure Ar, the diffusion coefficient along the z direelion is an increasing function as the loading increase and reaehcs a maximum value at some intermediate loading level, and then it decreases at higher loading level. But in the y direction, the diffusion coefficient decreases monotonically as increasing of the loading. For SF~ and CF4 , the diffusion eocffieients along the y direetion were same as the function of Ar in the z direction. Then the diffusion eoefficients of binary components SF6/CF4 in zeolite ITQ-3 had heen studied using molecular dynamic simulation methods. It was noted that the diffusion coefficients of binary components retains the trend of their pure component, however CF4 diffused much more slowly in the mixture than as a pure speeies. Compared to the pure SF6 , the diffusion coefficient of SF6 in the mixture was increased. It appears to he due to the influence of coupling effect between diffusing species.

关 键 词：扩散系数 分子动力学 ITQ-3分子筛 

分 类 号：TQ424.25[化学工程] TQ021.4