Adsorption example

Loaded Adsorbents. Where highly efficient removal of a trace impurity is required it is sometimes effective to use an adsorbent preloaded with a reactant rather than rely on the forces of adsorption. Examples include the use of 2eohtes preloaded with bromine to trap traces of olefins as their more easily condensible bromides 2eohtes preloaded with iodine to trap mercury vapor, and activated carbon loaded with cupric chloride for removal of mercaptans. 

SOLUTE ADSORPTION EXAMPLE OF Na+ BINDING TO THE GILL SURFACE... 

Examples Caustic + water Intense mixing Concentrated acid + aqueous solution Carbon adsorption Examples Low-intensity powder blending Dilution with similar solvent Screening Drying... 

Hower, J. C., Finkelman, R. B., Rathbone, R. F. Goodman, J. 2000. Intra- and inter-unit variation in fly ash petrography and mercury adsorption examples from a western Kentucky power station. Energy and Fuels, 14, 212-216. 

Homolytic and heterolytic relate in the usual sense to the formal nature of the cleavage of a single bond. If the electron pair in the bond of the adsorptive A B is divided in the course of its dissociative adsorption, the adsorption is homolytic dissociative adsorption. If A or B retains the electron pair, the adsorption is heterolytic dissociative adsorption. Examples follow. 

Because of the millisecond time scale for these reactions, pressure-pulse perturbation (Fig. 4.1) with conductivity detection of the response can be used, as in the molybdate adsorption example. Evidently, the inner-sphere surface complexion step for sulfate occurs on time scales very much longer than those for its outer-sphere surface complexation, and therefore it was not observed experimentally with the method used. 

FIG. 16-21 Bed profiles fortwo-component isothermal adsorption, Example 10. 

In general, adsorption of the olefin competitively inhibited adsorption of oxygen. However, only those olefins with some sort of activating substituent were adsorbed in quantities comparable to oxygen and were capable of fully supressing its subsequent adsorption. Examples of intermediate reactivity, such as vinyl bromide, appear to be indicative of a multiplicity of reactive sites. That is, not all sites reactive towards oxygen are also... 

Although the presence of these species does not necessarily lead to a chemical reaction on the surface, they certainly affect the efficiency of physical adsorption. Examples are adsorption of water or alcohols, which is greatly... 

FIGURE 9.28 (See color insert.) Results for the adsorption example. 

Note Use of equations (7.1.13d, e) is not recommended for determining 7 = (L/t, ) for adsorption examples with nonlinear equilibrium behavior since the characteristic lines for different concentrations can overlap, a physically Impossible situation (Sherwood et al, 1975 Wankat, 1986). 

For the VLE example we can specify only two of the three variables (T, P, and one mol fraction in one of the phases) then all the others are fixed. For the adsorption example we can specify three from this list. This is discussed as a phase-rule problem in Chapter 15. 

In summary, DFT-based electrochemical models with different complexity and computational costs are presented. For the ion adsorption example considered here, the inclusion of solvation stabilizes the adsorbed anion owing to the formation of hydrogen bonds with the adsorbed species. By comparison with solvation, inclusion of dipole moment-electric field interactions, polarization of the interface through an applied field, or a fully electrified interface through the double-reference method result in minor differences. Results of these different models are further compared in the voltammogram simulation in the following section. 

This linear free energy, vacuum interface approach is the simplest model for a reaction involving proton-electron transfer. The effect of the electric field can also be estimated with the consideration of the dipole moment change between reactants and products (Model 2a.2) or application of an electric field (Model 2a.3). The dipole moments are 0.10 and —0.04 e A for O2 and OOH, respectively, on a 3x3 Pt(lll) surface. Assuming the double layer thickness is 3 A, the field at a potential of 1 V is 0.33 V A The correction energy due to the electric field is —0.33 (—0.04 — 0.1)= +0.05 eV. This correction term is + 0.09 for OH reduction to H2O (/r = 0.07 and —0.21, respectively). The effect of an applied electric field could be included in the same manner as the ion adsorption example. 

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