Adsorption temperature- and

The variation of refrigeration COP with heat rejection temperature (final bed adsorption temperature and condensing temperature are assumed equal) and the maximum cycle temperature is illustrated for an evaporating temperature of-5°C in Fig. 8. Heat pmnp COP s follow similar trends but are higher. 

Figure 4.45. Thermal desorption spectra (bottom) and corresponding catalyst potential variation (top) after electrochemical O2 supply to Ag/YSZ at 260-320°C at various initial potentials Uwr Each curve corresponds to different adsorption temperature and current, thus different values of Uwr, in order to achieve nearly constant initial oxygen coverage.31 Reprinted with permission from Academic Press.

Adsorption behavior and the effect on colloid stability of water soluble polymers with a lower critical solution temperature(LCST) have been studied using polystyrene latices plus hydroxy propyl cellulose(HPC). Saturated adsorption(As) of HPC depended significantly on the adsorption temperature and the As obtained at the LCST was 1.5 times as large as the value at room temperature. The high As value obtained at the LCST remained for a long time at room temperature, and the dense adsorption layer formed on the latex particles showed strong protective action against salt and temperature. Furthermore, the dense adsorption layer of HPC on silica particles was very effective in the encapsulation process with polystyrene via emulsion polymerization in which the HPC-coated silica particles were used as seed. 

A similar correlation was obtained also for the experiments of Figure 3, where oxygen adsorption temperature was varied. The sensor resistance at 300 8C is shown as a function of the adsorption temperature in Figure 7. The resistance increased with increasing adsorption temperature, and then decreased via a maximum. The variation corresponds roughly well with that of the total amount of surface oxygens. 

The adsorption and subsequent reaction of ethylene on Group VIII metal surfaces provides a rich chemistry, which depends upon the adsorption temperature and the Group VIII metal. 13c NMR offers great potential to investigate the adsorbed states and to follow the reaction of ethylene on the surface. The study of the reactions of ethylene on Ru surfaces by 13c NMR has been reported by Gerstein and coworkers.(7,2) They have shown that ethylene on silica-supported ruthenium is converted to ethane, n-butane, 2- butenes and strongly adsorbed alkyl groups. 

Fig. 6 Yardstick-plot (Eq. 1) of N220 (triangle) and a graphitized N220g (filled circles) with adsorption cross section a determined from the bulk liquid density p (Eq. 2) 1 argon, 2 methane, 3 ethane, 4 propane, 5 iso-butane, 6 n-butane The slopes yield for N220 ds=2.56 0.04, for N220g ds=2.32 0.03. Adsorption temperatures and densities p are chosen according to the evaporation points of the gases at 1000 mbar...

The rate of contaminant adsorption onto activated carixm particles is controlled by two parallel diffusion mechanisms of pore and surface diffusion, which operate in different manners and extents depending upon adsorption temperature and adsorbate concentration. The present study showed that two mechanisms are separated successfully using a stepwise linearization technique incorporated with adsorption diffusion model. Surface and pore diffiisivities were obtained based on kinetic data in two types of adsorbers and isothermal data attained from batch bottle technique. Furthermore, intraparticle diffiisivities onto activated carbon particles were estimated by traditional breakthrough curve method and final results were compared with those obtained by more rigorous stepwise linearization technique. 

The adsorbents are activated in vacuo below 10" torr at 350°—400°C for 16 hours. Desorptions are carried out by repeatedly connecting the adsorption chamber to an evacuated vessel from which the desorbate is collected in a mixing chamber. Desorptions usually are carried out at the adsorption temperature, and completeness of removal is checked by material balance it is usually within 2%. Occasionally, to speed up the procedure, desorptions may be carried out at elevated temperatures. 

The acid-base properties of the decationated HY zeolites have been extensively studied with adsorption microcalorimetry. Tables II and III present a summary of calorimetric studies of the adsorption of ammonia and other probe molecules on HY zeolites with different Si/AI ratios, preparation methods, pretreatments, adsorption temperatures, and sodium contents. The large variety of conditions used in these studies complicates the comparison of the materials. For example, the initial differential heat of ammonia adsorption at... 

Summarizing the experimental observations, it follows that (i) no change in the spectrum of adsorbed benzene was detected with increasing loading and adsorption temperature and no irreversible consumption of benzene was found at 453 K. (ii) Very fast oligomerization of propene occured even at room temperature. With increasing temperature above 473 K, intensive formation and decomposition of unsaturated carbenium ions was detected. A broad IR... 

The uptake of molecules into the a-CO phase appears to be very dependent on the adsorption temperature and the gas phase pressure. Ehrlich quotes an a-phase concentration when CO is adsorbed at 130°K as being approximately 30 times that at room temperature during the early stages of adsorption since at the lower temperature the concentration of this phase increases earlier in the adsorption sequence. The variation in a-phase concentration with pressure was found to be less significant, but could be readily observed for temperatmes close to, or above, room temperature. The )3 phase on the other hand was found to be totally independent of pressure. 

The amounts adsorbed at equilibrium corresponding to adsorption capacity obtained from breakthrough curves, were deterrnined for different adsorption temperatures and for different xylene pressures, yields to isotherms shown in Figure 4. The isotherms are represented in the form of N = f (P) where N is the adsorbed amount per adsorbent weight... 

Effects of solvent-concentration, adsorption temperature and pressure.1526... 

Overall Reaction and Energetics of Chemical Adsorption at the Cold/Thiol Interface When we prepare SAMs onto gold substrates by the solution deposition method, it is not easy for us to decide the most suitable preparation conditions in terms of solvent, solution concentration of the component, adsorption temperature, and immersion time. This is because... 

In order that adsorption microcalorimetry can give an accurate representation of active site strength distribution the adsorbed probe molecule must be equilibrated among all sites on the catalyst surface within the time frame of the experiment. If external or internal mass-transfer limitation exists the adsorption on surface sites is controlled by kinetics instead of thermodynamics [5]. In this case the profile of differential heats as function of coverage would not accurately represent energy spectrum of the surface active sites and the adsorbent surface would appear to be more homogeneous. For these reasons, it is important to study the effect of the adsorption temperature and verify that molecules possess sufficient thermal energy to obtain the thermodynamically stable site occupation. 

Effects of solvent-concentration, adsorption temperature and pressure For safety reasons the concentration of combustible solvent vapors should be less than 50% of the lower explosive limit. The adsorption capacity of adsorbents increases as the concentration of the solvents increases. But the length of the MTZ is proportional to the solvent concentration. Because of the adsorption heat, as tire adsorption front moves through the bed also a temperature front follows in the same direction. To deal with the adsorption heat the inlet solvent concentration is usually limited to about 50 g/m. ... 

---