Donohue MD, Aranovich GL
Department of Chemical Engineering, The Johns Hopkins University, Baltimore, Maryland, 21218
J Colloid Interface Sci. 1998 Sep 1;205(1):121-30. doi: 10.1006/jcis.1998.5639.
Hysteresis has been observed in adsorption isotherms for a number of gas-solid systems and, generally, is attributed to adsorption in mesoporous materials with capillary condensation. This behavior is classified as Type IV or Type V in the IUPAC classification scheme. Here, lattice theory is used to predict adsorption behavior in pores. The Ono-Kondo theory is used with appropriate boundary conditions for fluid adsorption in infinite and semi-finite slit-like pores. It is shown that there can be phase transitions in the adsorbed phase which lead to hysteresis in kinetically controlled experiments. However, hysteresis in equilibrium behavior is exhibited only in pores of finite length. For finite-length pores, the interface geometry is predicted to be different during the processes of adsorption and desorption and this difference in interface shape leads to hysteresis. This simple molecular model is able to predict the change in the interface geometry without invoking the Kelvin equation or the macroscopic concept of surface tension. Copyright 1998 Academic Press.
在许多气固系统的吸附等温线中都观察到了滞后现象，一般来说，这归因于中孔材料中伴有毛细管凝聚的吸附作用。在国际纯粹与应用化学联合会（IUPAC）的分类方案中，这种行为被归类为IV型或V型。在此，晶格理论被用于预测孔中的吸附行为。小野 - 近藤理论结合了适用于无限和半无限狭缝状孔中流体吸附的边界条件。结果表明，吸附相中可能存在相变，这会在动力学控制实验中导致滞后现象。然而，平衡行为中的滞后现象仅在有限长度的孔中出现。对于有限长度的孔，预计在吸附和解吸过程中界面几何形状会有所不同，而这种界面形状的差异会导致滞后现象。这个简单的分子模型能够预测界面几何形状的变化，而无需援引开尔文方程或表面张力的宏观概念。版权所有1998年学术出版社。
