Adsorption equipment sizing example

We turn now to the analysis of pore structure. For this purpose, various optional computational procedures are incorporated in the software, which is now provided with most commercial adsorption equipment. For example, for micropore size analysis the isotherm can be converted into a t-plot and also displayed in either the Dubinin-Radushkevich (DR) or the Dubinin-Astakov (DA) coordinates. With some packages it is also possible to apply the MP method of Brunauer, the Horvath-Kawazoe (HK) method and/or density functional theory... 

Figure 12.6 shows a scheme of the laboratory equipment used to test this set-up. Figure 12.7 is an example of the iodate concentration versus bed volume (BV) plot during one cycle of the adsorption-desorption process. Figure 12.8 shows the influence of the resin size on the extent of iodate removal. The particle size of the resin greatly influences the removal. The fluidised bed volume increases as the diameter of the resin reduces. 

Care must be taken in selecting an indirect method since these require assumptions about either the real size distribution, the shape, or the process on which the analysis is based. For example, conductometric sensing zone equipment relies on the assumption of sphericity, which is usually reasonable for emulsion droplets, but often is not reasonable for particles in a suspension. Similarly, light-scattering techniques are reliable only if the particle shape and refractive index are known or assumed, and adsorption analyses rely on model adsorption isotherms, the uniformity of particle size and porosity, and the orientation of adsorbed species. Each technique has its own limitations. For example, concentrated dispersions... 

---