Lag-ring and pore structural model

For a catalyst, adsorption isotherm should be unique. During measurement, the actual porous catalyst will give an isotherm in the adsorption process, while giving 

The pore structures of various solid are very anfractuous and multifarious, and their lag rings are different from each other. Der Booer considered that it would not exceed the five kinds of a, b, c, d, e as shown in Fig. 7.10. In the study of pore structure of catal3dic materials, the analysis of these five lag rings can help to provide useful information for the understanding of the pore structural characteristics and for the reasonable choice of the pore structural models. 

Fig- 7.11 Typical pore model reflected by a-type back line rn — Narrow-pore radius fw — Wide-pore radius 

12 Typical pore model reflected by B-type back line (a) Cubicles separated by accumulation model (b) Cnbicles separated by small particles (c) Typical isothermal loop of montmorillonite 

The five kinds of lag rings reflect the typical pore structural information. The real catal3dic materials are rarely similar, mostly as superposition-like of various lag rings, which reflects the complexity of the pore structure. This analysis should be used to identify the main types of pore structure. 

---