Saturation adsorption

Figure 5.28, effect 4). This process approaches an equilibrium called adsorptive saturation. 

The discussed effects, such as evaporation and adsorptive saturation, are prevented by placing a counter plate at a distance of one or a few millimeters from the chromatographic layer. The development with such a reduced vapor phase in the so-called sandwich chambers (S-chambers) can improve the separation. The glass-backed 20 X 20 cm plate forms one wall of the chamber with the adsorbent facing inward. A glass plate with spacers, called counter plates, is clamped to this plate and forms the other wall of the chamber (Figure 5.31, left [32]). 

Frank-van der Merve (strong adsorption, saturated to bulk phase) Monolayer spreading parallel to the interface — niAal/othin film) A/u >0 (thick film) Aa < 0 or 2a < a Cj — e [Pg.144]

Interpretation of infrared spectra of zeolite omega is inconsistent with the proposed structure (16) and is more consistent with a structure based on sodalite-type units (17). The adsorption saturation values can only be accounted for by the proposed structure if it is assumed that H20 and N2 can occupy the gmelinite-type cages. However, this proposed structure does not provide for access to the gmelinite-type units from the main channel which are large enough to pass N2. Access to the two dimensional... 

Figure 7 shows adsorption isotherms for this protein on the different sorbents. The adsorption plateau-values at PS-(EO)8, approximately 2.5 mg m 2, is compatible with a complete monolayer of side-on adsorbed a-chymotrypsin molecules. Adsorption saturation at the PS and, even more so, the Teflon surfaces, is beyond monolayer coverage suggesting that on these hydrophobic surfaces the protein molecules are severely perturbed as to accommodate more protein mass in the adsorbed layers and/or adsorption of a second layer of protein molecules (possibly triggered by structurally altered molecules in the... 

Il e degree of adsorption saturation and the area occupied by an emulsifier molecule in the satiuated adsorption layer on the surface of latex particles were determined by means of the adsorption titration method (16). Sizes of latex particles were determined... 

The above analysis demonstrates that the coordination of oxyanions varies by the anion species. And it accords well with the stoichiometry of oxyanion / Fe at the adsorption saturations. The coordination structure of en is still unclear and the data analysis is in progress in order to clarify the origin of the small coordination numbers after the adsorption of anions. 

Monomer Initial SDDS cone in aqueous phase (moVdm x 10 ) Lates cone Cfl Coagulutn monomer (%> Particle diameter (um) 7 (mJ/m ) Additional adsorbed amount of SDDS (moVgof polymer x 10 ) Sliro Degree of adsorption saturation fe)... 

Similar data on the adsorption saturation of acrylate latexes (based on EA, BA, and 2-EHA) synthesized with the same emulsifier were obtained recently by Snuparek and Tutalkova (1978), A lesser degree of filling of the adsorption layer, 46.5 and 49.6%, was observed for more hydrophobic monomers (2-EHA and BAK with a greater degree being observed in the polymerization of the more hydrophilic EA, 66.3%. 

These results favor a model originally proposed by Koel et al. (15) wherein CO and H compete for the same adsorption site corresponding to the most-strongly-bound states (a.-C0 and B.-H). The a.-C0 state has a higher heat of adsorption and hence displaces B.-H states to either B2 or Z sites upon adsorption. Saturation of the B2 H states completely blocks adsorption of CO into the weaker a -C0 sites (desorption temperatures from 300-400 K). 

Figure 4.67 shows adsorption isotherms of three anionic surfactants on alumina at favorable electrostatic conditions, namely, of p-3-nonyibenzene sulfonate in the presence of 0.01 mol dm " NaCl at pH 4.1 (Ref. 737), of n-decylbenzene sulfonate at 40 C, at pH 4 in absence of supporting electrolyte (Ref. 717), and of dodecyl sulfate at pH 5.3 in the presence of 0.1 mol dm" NaCl (Ref. 718). The solution concentration and adsorption density in Fig. 4.67 were normalized to the transition point IH/IV, which corresponds to CMC and adsorption saturation. In... 

The sharp reduction in the adsorption saturation level when one wt.% NaCl is added to the solution seems to be associated principally with the effect of electrolyte on the structure of the electrical double layer and on the influence of NaCl on the CMC of the surfactants. The CMC decreases as the ionic strength of the solution increases and this has the effect of reducing the maximum surfactant monomer concentration. 

The condition for the stagnant cup formation, the surface concentration variation along the bubble surface, and the adsorption saturation near the rear stagnation point is determined in terms of Marangoni niunber. If the compressive viscous shear force exceeds the characteristic linear surface pressure force, i.e. at small Marangoni numbers, the adsorption layer is compressed considerably and no saturation near the rear stagnation point can result. 

Adsorption to a monolayer had been explained most successfully by Irving Langmuir. This very success may have deflected attention from the study of multilayer adsorption. In monolayer adsorption, saturation is approached when the monolayer has been filled. But soon after this has occurred, additional adsorption sets in, thus producing a curve that has been called S-shaped although it is necessary to lay the S on its side in order to reproduce the graph. 

The O2 is initially adsorbed in molecular form as a peroxide-like compound, which rapidly dissociates with release of energy (Fig. 5-20 b). Since the oxygen atoms require several free centers for adsorption, saturation coverage with oxygen is rapidly reached. 

Eq.l indicates that effective diffusion coefficient of gas in the pea coal was influenced by the porosity and bending coefficient. Swelling of coal matrix owing to gas adsorption reduced the porosity meanwhile gas adsorption changed the bending coefficient of the diffusion channel and led to the increase of the diffusion resistance. Conversely, gas emission had an impact on the diffusion resistance of gas on the condition of isothermal and iso-baric after gas adsorption saturation (Chen Ruijun... 

This section in a similar way as the previous one summarizes a number of studies on the adsorption saturated and unsaturated diacids to (oxy)(hydr)oxide minerals. The chemical speciation (in terms of the number of species in solution) becomes more complex for these compounds, which concomitantly enhances the possibilities of the diacids to form surface complexes of different stoichiometries in terms of bonding and proton balances. The diacids addressed are summarized in tables 3 (saturated diacids) and 4 (imsaturated diacids). The remainder of the section discusses in some detail published findings from ATR-FTIR spectroscopy. 

On the basis of the IR data, the general consensus is that when minerals exhibit 100% flotability, several types of chemisorbed oleate as well as precipitated calcium oleate are present at the surface, in agreement with the initial hypothesis of Peck [425]. However, there is controversy concerning the assignment of the adsorption bands of adsorbed oleate and, hence, the structure of surface species. It stems from the strong dependence of the oleate-calcium coordination on the deposition and precipitation conditions-an effect well known for L monolayers and LB films of alkanoates [426]. The amount of oleate adsorbed on a fluorite slab, as measured by IR spectroscopy, is quite different than that for fine fluorite particles [412]. For the slab, there exists an adsorption saturation point, but for fine particles, the amount of adsorbed oleate increases with concentration, although the concentration dependence of the amount of oleate in the... 

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