Organic chemicals, adsorptive separation

The second part of the book covers zeolite adsorptive separation, adsorption mechanisms, zeolite membranes and mixed matrix membranes in Chapters 5-11. Chapter 5 summarizes the literature and reports adsorptive separation work on specific separation applications organized around the types of molecular species being separated. A series of tables provide groupings for (i) aromatics and derivatives, (ii) non-aromatic hydrocarbons, (iii) carbohydrates and organic acids, (iv) fine chemical and pharmaceuticals, (v) trace impurities removed from bulk materials. Zeolite adsorptive separation mechanisms are theorized in Chapter 6. 

As stated earlier, distillation and related vapor-liquid operations are by far the most common separation processes In the organic-chemical, petroleum and allied Industries It Is unlikely that adsorption will ever rival distillation In frequency of use, but adsorption s share of the separation task should grow substantially The purpose of this section Is to indicate the likely areas of growth in existing and new applications, as well as the technological Innovations which would foster this growth ... 

Ti olecular sieves have been used thus far to separate distinct classes of organic compounds. The separation of n-para Bns from branched paraffins with 5A molecular sieves is well known. Selective adsorption of aromatics from mixed streams with lOX, 13X, and type Y sieves is perhaps less widely known. The use of lOX molecular sieves to separate mixtures of aromatics has been disclosed 1,2,3). These patents disclose separations of mixtures of monocyclic aromatics 1, 2) and dicyclic aromatics (3). These were the first indications that molecular sieves could separate compounds within a single chemical class. 

While these characteristics are reviewed separately as reflected by numerous AC modification research, it should be noted that there were also research with the direct intention of significantly modifying two or more characteristic and that the teehniques reviewed are not intended to be exhaustive. The adsorption capacity depends on the accessibility of the organic molecules to the microporosity that is dependent on their size [5]. AC can be used for removing taste and odor (T O) compoimds, synthetic organic chemicals (SOCs), and dissolved natural organie matter (DOM) from water. 

This is another metal oxide used in thin-layer applications. The chemical formula is AI2O3. On aluminum oxide thin-layers sorption is based on partial positive and negative charges on the surface and any water sorbed thereon. In the manufacturing process aluminum oxide can be made to have a basic surface (pH 9-10), a neutral surface (pH 7-8), or an acidic surface (pH 4-4.5). This allows for a different type of adsorption separation based solely on surface pH. Other properties of the different aluminas available for TLC are shown in Table 2. The different pore size and surface area types will also impart different separation characteristics to these sorbent layers. Layers of this sorbent are available with and without binders both organic and inorganic. A whole range of... 

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