Adsorption quantities

For the sake of clarity the most important consequences of spillover are summarized and discussed in the following four subsections. First, the enhanced adsorption by mono- and bimetallic supported catalysts is described. This deals mainly with abnormal hydrogen adsorption quantities... 

Derivation of the adsorption quantities from calorimetric data. 45... 

Derivation of the Adsorption Quantities from Calorimetric Data... 

We now proceed with the calculations of the thermodynamic adsorption quantities for a surface possessing a lower degree of symmetry, via a surface whose properties vary periodically along one dimension, say x, and do not depend on another lateral coordinate, y. For such a system, expression (1) becomes... 

Up to this point the essential equations have been presented. Now, it is possible to analyze the work carried out in connection with the classical thermodynamic approach. The first systematic study of a thermodynamic adsorption quantity was perhaps the work done by de Boer and coworkers [10] on the determination, interpretation and significance of the enthalpy and entropy of adsorption. Their papers analyzed almost all aspects of the experimental determination of the entropy and how to interpret the values obtained in terms of two extreme models, i.e., those of mobile and locahzed adsorption, which today have lost much of their usefulness. To catalog the behavior of the adsorbed film as localized or mobile is a very simplistic solution and it has been demonstrated [9] that in most cases the adsorbed film is neither completely localized nor completely mobile. This approach also is somehow outdated because numerical simulations provide a better microscopic interpretation of the system s behavior. 

For the adsorption from a solution into a solid, the Langmuir equation is often used to describe the equilibrium isotherms. But the parameters in the Langmuir equation should not be considered as having the same physical meaning as those used for the vapor adsorption. Nevertheless, the parameters n and b in Equation (10a) can be used for comparison as n may indicate the "saturated" adsorption capacity and b is related to the initial slope of the isotherm. The liquid adsorption equilibrium results given in Table II show that the saturation adsorption capacity for the five alcohols decrease in the following order (based on the adsorption quantity in mmol/g) ... 

The study of the phosphorus adsorption in the Changjiang River Estuary sediments showed that the sediments were buffers to phosphate and the balance time of phosphorus adsorption (desorption) was about 6 h. The saturated adsorption quantity of phosphorus was about 600 pg/g and the saturated desorption was about 126.37 pg/g. The apparent adsorption heat of fine sediments (AH) was 47.59 kJ/mol. The adsorption of phosphate was in accordance with Freundlich s isothermal equilibrium and it was a heat absorption reaction. The contents of sand and mud in sediments had some influence on adsorption and the adsorption would decrease with the increase in sand or mud content. In general, the increase in pH favors adsorption. Moreover, the increase in salinity does not favor adsorption but favors desorption. The research shows that the release of phosphorus in the sediments of the Changjiang River Estuary... 

When alternative electromagnetic field is exerted in adsorptive step, typical experimental result is shown in Figure 2, Figure 3, Figure 4 and Figure 5 in which y axis represent gas adsorptive quantity calculated indirectly from every ton of coal adsorptive quantity and x axis represent adsorptive balance pressure. Figure 2 and Figure 3 show the adsorptive results which the volt of alternative... 

Carry out measurement of adsorption quantity on the basis of the previous settings. The adsorption isotherm of coal samples will be automatically generated. 

It can be seen from Fig. 2 that the Nj adsorption isotherm of coal samples in different size show similar trends. The adsorption quantity of Nj increases with the increase of relative pressure p/p , and the adsorption quantity of Nj also increases with the increase of coal size. 

The effect of contact time on adsorption was given in Figure 3. The adsorptive quantity of Cu + increased with increase in contact time and reached equilibrium after 180 min. So keeping these observations in view, 180 min contact time was opted for further experiments. 

Simple metal single crystals prepared under well-controlled conditions are extensively characterized with respect to their geometric and electronic properties [28, 29]. With techniques such as MBS, one can describe details of reaction mechanisms and obtain reaction probabilities and rate constants for elementary reaction steps, activation barriers for surface processes, and adsorption quantities [30-33], Kinetic data from single crystal experiments may be vastly different from that of technical... 

Similar to the surface science approach, TAP is useful for determining rate constants of elementary reaction steps, activation barriers for surface processes, and adsorption quantities. Surface science techniques utilize well-defined model systems and are useful for understanding the substituent parts of a complex system. The TAP technique uses real materials with complexity intact which makes it possible to study how the system works together to present emergent properties (properties that are more than just the sum of parts), for example, how does surface composition influence surface-to-bulk transport which then manifest an effect on the global kinetics ... 

Murata, Y., Tokui, S., Watanabe, S., Daisho, Y., Suzuki, H., Ishii, H., (2008) Improvement of NOx Reduction Rate of Urea-SCR System by NH3 Adsorption Quantity Control, SAE Technical Paper 2008-01-2498, doi 10.4271/2008-01-2498. 

Pore distribution in general is calculated according to the desorption isotherm, which is a desorption process with equilibrium steam pressure descending and adsorption volume reducing. The relationship between the total adsorption quantity and pore radius is shown in Fig. 7.8. The relationship between the differential values of adsorption quantity vs. pore radius is the so-called pore distribution curve, as shown in Fig. 7.9. 

Fig. 7.8 Relationship between the total adsorption quantity and pore radius...

The radius ro corresponding to the maximum value of curve in Fig. 7.9 is known as the most probable pore radius. It means that the proportion of the pore whose radius ro is the highest in the porous catalyst. In order to obtain the curve of pore size distribution, it needs to detect the contribution of a variety pore on the adsorption quantity, and then use the following ways to calculate the relationship of pore size distribution according to the scope of pore size of a variety of materials. 

The chemisorptive state of oxygen significantly exceeds the single-layer saturated adsorption quantity for many metals. This shows that the absorbed oxygen can penetrate into the bulk-phase of catalyst. With isotopic tracer experiments, it can be proved that the lattice oxygen in metal oxide is also involved in the reactions. 

The integral enthalpy Aj yH entropy (A2i5 ), and free enthalpy (A2]G of bulk dilution provide the Unk between the corresponding displacement and adsorption quantities [10,12,37,39] ... 

---