应用吸附势理论研究氢在沸石上的超临界吸附

针对吸附势理论描述气体超临界吸附所面临的问题, 采用经验方法求取了临界温度以上且较宽的压力范围内氢在微孔沸石上吸附的虚拟饱和蒸汽压和该吸附体系的亲合势系数茁i,j, 并通过对ln(W/W0)与(着i,j/茁i,j) (W,W0分别为吸附相体积及吸附剂的饱和吸附容量, 着i,j为吸附势)的相关性分析得到了一般吸附函数的表达式. 研究结果表明, 茁i,j与吸附热qi,j具有线性关系, 因此可将吸附热作为一般吸附函数的参数应用于吸附势理论的研究. 利用一般吸附函数对本实验条件下的吸附数据的拟合分析证实该函数可较好地表述氢在微孔沸石上的超临界吸附.

Application of the Adsorption Potential Theory to Hydrogen Adsorption on Zeolites above Critical Temperature

The adsorption potential theory was applied to study the adsorption isotherms of hydrogen on four kinds of zeolites above critical temperature and under a wide range of pressure. An approximate treatment was used to obtain the pseudo-saturated pressure of supercritical hydrogen and the affinity coefficients of adsorption systems under study. A formula for the generalized adsorption function to describe supercritical adsorption of hydrogen on zeolites was derived by the analysis of the functional dependence of the adsorption amount on the adsorption potential and the affinity coefficients. The study showed that the affinity coefficients had a linear relation with the adsorption heat, which could be used as a parameter of the generalized adsorption function in characterization of an adsorption system. The fittings of the generalized adsorption function to experimental data exhibited that the hydrogen adsorption on zeolites above critical temperature could be satisfactorily described by the generalized adsorption function.