超临界氢在活性炭上的吸附等温线研究

Study on the Adsorption Isotherms of Supercritical Hydrogen on Activated Carbon

通过77－298K范围内氢在AX-21活性炭上的吸附数据，探讨如何用普通I-型等温线模型处理超临界条件下的吸附等混线，以获取关于超临界吸附系统的正确信息结果表明，Langmuir方程虽然可用来表达实验数据，但不能提供关于该吸附系统的任何可靠信息；Virial方程虽不是整组数据的最好模型，但却能够可靠地确定Henry定律常数，然后可从vantHoff标绘决定等量吸附热.通过将实验数据拟合到Dubinin－Astakhov方程，讨论了某些吸附机理．虽然该方程可以最好地表达实验数据，但由于其中的四个参数在回归过程中存在不同程度的相互作用，以及方程中某些物理量在超临界领域定义的不严密性。

The aim of this paper is to study how to treat the experimental adsorption isotherms by the conventional Type－I isotherm theories in order to acquire the required information of the adsorption system under supercritical conditions． The study was carried out on manipulation of a set of adsorption data of supercritical hydrogen on activated carbon AX－21 over a temperature range of 77－298K． The results show that the Langmuir equation can well model the experimental data, but cannot provide any reliable information about the adsorption svstem considered; the Virial equation cannot model the whole set of data satisfactorily, but it can give Henry's law constants rellably， from which lsosteric heat of adsorption can then be precisely determined Some inspection of the adsorption mechanism was fitting data to Dubinin-Astakhov equation .Although this equation can best model the experimental data． the reality of any physical quantity evaluated from it might be doubtful since the parameters in the model interact each other during regression and some quantities in the equation are ill－defined under supercritical condition．