Evaluation of the energy distribution function from liquid/solid adsorption measurements
Evaluation of the energy distribution function from liquid/solid adsorption measurements
复制标题
通过液体/固体吸附测量评估能量分布函数
DOI：
10.1021/la00034a012
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发表时间：
1993
期刊：
影响因子：
3.9
通讯作者：
M. Jaroniec
中科院分区：
文献类型：
--
作者：
M. Heuchel;P. Braeuer;M. Szombathely;U. Messow;W. Einicke;M. Jaroniec
本文讨论了由二元非电性液体混合物在非均质固体表面上的超额吸附等温线所得到的吸附能量分布函数F(Ui)的数值计算的各种问题。文献中已知的一些方法没有解决积分方程数值不适定的问题，积分方程常用于计算F(f/21)。在目前的工作中，已经提出了两种替代的方法，它们考虑了该积分方程的病态性质。在第一种方法中使用了正则化方法，而在第二种方法中使用了Stieltjes变换的展开。此外，还考虑了局部吸附模型的选择问题。用AFT图的形式表示总的超额吸附等温线对选择该模型是有用的。对不同混合物在同一吸附剂上和一种混合物在不同吸附剂上进行了算例计算。例如，方法论方法对于分析所研究的系统之间的差异特别有用。用正则化方法计算并比较了正己烷/正己醇、正己烷/甲苯和正己醇/甲苯在活性碳上的分布函数F(t/21)。对水/乙醇在不同硅铝比的ZSM-5沸石上的IWN函数进行了另一种比较。
Various problems associated with numerical evaluation of the adsorption energy distribution function, F (Uii), from the experimental excess adsorption isotherms of binary nonelectrolytic liquid mixtures on heterogenous solid surfaces have been discussed. Several methods known in the literature did not address the numerical ill-posed character of the integral equation, which has been used for calculatingF (f/21). In the current work two alternative approaches, which take into account the ill-posed nature of this integral equation, have been presented. In the first approach a regularization method has been employed, whereas in the second one an expansion of the Stieltjes’ transformation has been utilized. Also, the problem of choice of the local adsorption model has been considered. A representation of the overall excess adsorption isotherm in the form of the Aft-plot has been found to be useful for selecting this model. Illustrative calculations have been carried out for various mixtures on the same adsorbent and for one mixture on different adsorbents. Such as methodological approach is especially useful for analyzing differences between the systems studied. By use of the regularization method, the distribution functions F (t/21) for n-hexane/1-hexanol, n-hexane/toluene, and n-hexanol/toluene on an active carbon have been calculated and compared. Another comparison of the IWn) functions have been presented for water/ethanol on ZSM-5 zeolites of different Si/Al ratios.