Competitive adsorption behavior

Due to the strong nonlinearity of the isotherms, combined with the competitive adsorption behavior, the triangle is completely different to that for linear isotherms. 

Unfortunately, the available experimental results suggest that the column saturation capacity is often not the same for the components of a binary mixture, so Eq. 4.5 does not account accurately for the competitive adsorption behavior of these components [48]. A simple approach was proposed to turn the difficulty (next subsection). Although it is applicable in some cases, more sophisticated models seem necessary. Numerous isotherm models have been suggested to solve this problem. Those resulting from the ideal adsorbed solution (IAS) theory developed by Myers and Prausnitz [49] are among the most accurate and versatile of them. Later, this theory was refined to accormt for the dependence of the activity coefficients of solutes in solution on their concentrations, leading to the real adsorption solution (RAS) theory. In most cases, however, the equations resulting from IAS and the RAS theories must be solved iteratively, which makes it inconvenient to incorporate those equations into the numerical calculations of column dynamics and in the prediction of elution band profiles. 

Migliorini et al. [65] used both the IAS and the RAS theory to accoimt for the experimental binary competitive isotherm data of the Troger s base enantiomers on microcrystalline triacetate cellulose (CTA), using ethanol as the solvent. For the calculations of the RAS theory, they used the Wilson model for the solution, including the empirical spreading pressure dependence [66]. They concluded that the IAS model imderestimates the extent of the competition between the two enantiomers in this system while the RAS model accormts accurately for the complex competitive adsorption behavior exhibited by these enantiomers. 

The main topics to be presented include the origins of the surface activity of proteins, multiple states of adsorbed proteins, and the competitive adsorption behavior of proteins. These topics were chosen because it appears that a better understanding of each is necessary... 

The sequence of reactions which take place by the activation of the coagulation system at the blood/biomaterial interface are summarized in Fig. 3. The competitive adsorption behavior of proteins at the biomaterial surface determines the pathway and the extent of intrinsic coagulation and adhesion of platelets. Predictions about the interactions between the biomaterial surface and the adsorbed proteins can only be formulated by having an exact knowledge of the structure of the biomaterial s surface and the conformation of the adsorbed proteins. These interactions are determined both by the hydrophobic/hydrophilic, charged/uncharged, and polar/non-polar parts of the proteins and the nature of the polymer surface [25-27]. A commonly accepted fact is that decreasing sur-... 

In this study, a binary adsorption of 2-methylphenol/2,4-dimethylphenol was performed on F400 and BC-21. Figure 6.8a and b presents the binary adsorption isotherms of phenoI/2-methylphenol for F400 and BC-21, respectively. Meanwhile, the Myers parameters obtained from the single solute anoxic isotherm was applied into the lAST model to predict the competitive adsorption behavior. The evaluation of the predictability of lAST was also done by calculating the sum of squares of relative errors (SSREs). All the detailed concentration combination and SSRE values of both runs for both adsorbents are shown in Table 6.4. 

It is well known that SMB is preferably conducted in nonlinear region to achieve higher productivity therefore it is more important to determine the competitive adsorption behavior among the feed species. In special, the non-stoichiometric Langmuir isotherm is important in SMB development since constraints on the flow rate ratios (i.e.,fftj,m2,fftj and m ) in SMB unit can be determined explicitly on the frame of equilibrium theory [8]. It can be expressed as ... 

Amebrant and Nylander used the technique to study the sequential and competitive adsorption behavior of " C-labeled jS-lactoglobulin with KT-casein on hydrophobic and hydrophilic chromium surfaces. The adsorption was also followed by in situ ellipsometry measurements, providing a basis for comparison of the two techniques as described in Section II. 1. 

The competitive adsorption behavior of two ions in the simple electrolyte solute, MA, can be examined in Figs 29 and 30. 

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