Adsorbent water content

Adsorption Plots. Isotherm plots are the most common method of presenting adsorption data. An isotherm is a curve of constant temperature the adsorbed water content of the adsorbent is plotted against the water partial pressure in equiHbrium with the adsorbent. An isostere plot shows curves of constant adsorbed water content the vapor pressure in equiHbrium with the adsorbent is plotted against temperature. Figure 13 shows isosteres for the three primary adsorbents described previously. In this case, the dew points for the three adsorbents are plotted at 0.5, 5, and 10 kg... 

H2O/100 kg of adsorbent. At equilibrium and at a given adsorbed water content, the dew point that can be obtained in the treated fluid is a function only of the adsorbent temperature. The slopes of the isosteres indicate that the capacity of molecular sieves is less temperature sensitive than that of siUca gel or activated alumina. In another type of isostere plot, the natural logarithm of the vapor pressure of water in equiUbrium with the desiccant is plotted against the reciprocal of absolute temperature. The slopes of these isosteres are proportional to the isosteric heats of adsorption of water on the desiccant (see... 

When developing a liquid phase adsorptive separation process, a laboratory pulse test is typically used as a tool to search for a suitable adsorbent and desorbent combination for a particular separation. The properties of the suitable adsorbent, such as type of zeolite, exchange cation and adsorbent water content, are a critical part of the study. The desorbent, temperature and liquid flow circulation are also critical parameters that can be obtained from the pulse test. The pulse test is not only a critical tool for developing the equilibrium-selective adsorption process it is also an essential tool for other separation process developments such as rate-selective adsorption, shape-selective adsorption, ion exchange and reactive adsorption. 

Overall, protein activity is affected by four major factors a) the ground state, thermodynamic stabilization of the protein, b) active site flexibility response to solvent polarity and adsorbed water content, c) the impact of water stripping from the protein on the active conformation and d) direct solvent induced perturbation of the protein (Dordick, 1992). 

Among the polar adsorbents, surface activity is intimately related to adsorbent water content. Almost all polar adsorbents lose water upon being heated, the water existing originally in the adsorbent as either (1) bulk water unassociated with the surface, (2) surface hydroxyl groups which... 

Fig. 11-7. Dependence of certain alumina properties on adsorbent water content. Reprinted from the Joiirtia/ of Chromatography (6) by permission of Elsevier Publishing...

When adsorbent samples from different batches or sources are sufficiently alike with respect to starting surface structure and surface area, it is possible to relate adsorbent water content, K , and a as in Table 6-1. In such cases the chromatographic properties of an adsorbent sample are defined by a single property adsorbent water content or activity. In theory it should be possible to standardize adsorbents of this type by simply adding a definite quantity of water during the deactivation step,... 

Table 22.3 shows how much water can be adsorbed in carbons when stored in 90%RH at 40°C for 70h. The adsorbed water content in Carbotron P (J) is dramatically decreased to less than half of that in Carbotron PS (F). Further experiments suggested that the adsorbed water content will be able to be decreased to less than 1% in near future. 

The true density of Carbotron P (J) is same as that of Carbotron PS (F). So, the pore volume in carbons is not changed. However, the capacity at the CV region and the adsorbed water content apparently are decreased. These phenomena imply that... 

Properly applied fatty acids provide the filler with a hydrocarbon-like surface, which is much less polar than the filler itself For example, the treatment of a precipitated calcium carbonate with a fatty acid coating was found to reduce the dispersive component of surface energy from 54 to 23 mj/m 3]. As a result, the filler is made more compatible with many polymer types, resulting in benefits such as faster incorporation and mixing, better dispersion, less energy consumption, lower viscosity, and easier extrusion. The filler generally also has lower adsorbed water content. 

The H NMR spectra of HjO/HPA/SiOj have significant distinctions in comparison with those for the parent nanosilica, and these differences depend not only on the adsorbed water content but also on reaction temperature, dispersion medium (Figure 1.131 and Table 1.24), and other parameters. Notice that the 5e(/t) function becomes more nonlinear with increasing temperature and this is accompanied by diminution of the 8e values (Figure 1.130b). 

Figure 26 I he dielectric constant of crystallized cellulose/chlorinated insulator oil against the adsorbed water content on the particle surface. The particle concentration is 10 wt%, the electric field frequency is 1000 Hz, and the temperature is 20 C. Redrawn from H. Uejima, Jpn. J. Appl. Phys., 11(1972)319.

Figure 45 The relative viscosity, the apparent viscosity at 1000 V devided by the viscosity at zero electric field, vs. the particle volume fraction of crystalline cellulose/chlorine suspension obtained at different shear rales. The adsorbed water content is 8.3 wt%. Redrawn from H. Uejima, Jpn. J. Appl. Phys. 11(1972 )319.

Chulalaksananukul et al. [88] compared the fiansesterification between propyl acetate and geraniol in SCCO2 and in n-hexane. The optimum adsorbed water content is 10% g/ g of support. They found an inhibition by geraniol and a ping-pong bi-bi mechanism. The... 

---