Sorption isotherm Langmuir

For a Langmuir sorption isotherm the net sorption rate can be written... 

FIGURE 5.20 Langmuir sorption isotherm of Br2 on cotton fibers. 

The modeled pattern in Figure 11 shows the observed concentration trends, but, clearly, it does not match the details. Notably, the predicted As peaks arrive too early and they are too small. The column experiments of Isenbeck-Schroter (1995) and Darland and Inskeep (1997) required kinetic reactions for Freundlich or Langmuir sorption isotherms for As, but a kinetic model appears to spread out the As concentrations in Figure 11 only, and it does not shift the position of the peak to later arrival times. Therefore, other reactions might explain the discrepancy. 

Howsmon, G.J., andN.A. Peppas, "Mathematical Analysis of Transport Properties of Polymer Films for Food Packaging. VI Coupling of Moisture and Oxygen Transport Using Langmuir Sorption Isotherms", J Appl Poly Sci 1986, 31, pp 2071-2082. 

Phosphorus sorption maximum as estimated by sorption experiments and Langmuir sorption isotherms = 1000 mg P/kg... 

When formulating a microkinetic rate expression r(T,x) one has to account for the sorption equilibria of the reaction components between the liquid phase and the active catalyst phase. For this purpose, since the liquid-phase reaction mixtures have a strongly non-ideal behavior, one should use generalized Langmuir sorption isotherms in terms of liquid-phase activities as proposed first in the pioneer work of Rehfinger and Hoffmann [45]. According to these authors, the sorption equilibria of the N species A on one active site S is given by... 

Alternatively, there may be cooperative absorption of the analyte so that, as the amount of analyte increases, the concentration in the stationary phase increases more rapidly than would otherwise be predicted. The plot of C ob against Cjiat consequently curves upward in a shape known as an anti-Langmuir sorption isotherm (Figure 2.13). This is less common than saturation of the stationary phase, but as some solutes (e.g., some acids) are absorbed in the stationary phase, they alter its nature so that they have... 

Figure 6.2. Langmuir sorption isotherms contoured for values of ranging from 0.3 to 30. r is 1 X 10" mol/m for each isotherm.

---