Adsorption isothenn

Gileadi combined adsorption isothenn, 340, 342, 344 Gileadi isotherm, application to electrode kinetics, 344, 347 Gouy-Chapman theory, 190, 193, 200 Graphical representation, (of impedance data), 431... 

Figure 1. Adsorption isothenns of (a) C2H4, (b) CzHs and (c) C3H6 on esh Ag(2.0)-FER(60.2) pre-evacuated at 500 °C for 0.5 h. C ten and closed circles conespond to the 1st and 2nd adsorption measurements (see text for the details).

From the experimental adsorption isothenns both heats of adsorption and surface areas can be derived. For nonlinear adsorption isothenns the heat of adsorption varies with surface coi r e and results are expressed as an isosteric heat of adsorption, at a specified coverage, a. 

SUiircdse type uptake curve lO c uptake at pH 5 and uptake a( pH 6- ) Linear Jog-log adsorption isothenns at constant pH, slope I 17 kJ/mol... 

Figure 3.14. Adsorption isothenn of 0104 at the quartz-water interface at pH 4 bulk solution. T = 300 K. ksnc = 290 nm. (From Mifflin et al., 2003 copyright 2003 American Chemical Society.)...

When more Chan one substance is present, the adsorption isothenn equations are somewhat more complex. The principles are the same, though, and the isotherm equations are easily derived. It is left as an exercise to show that the adsorption isotherm of A in the presence of adsorbate B is given by the relationship... 

In both cases, the LO curve shifts because catalytic sites are occupied by strongly adsorbed species that inliibit the reaction. According to LH theon, the inhibition is essentially governed by the adsorption characteristics at equilibrium without reaction. Consequently, adsorption isothenns luider non reacting condition must be measured. They yield the adsorption constants involved in a LH rate expression. 

Compounds 2-chlorophenol and 2,4-dichlorophenol offer special challenges for de-temiining ( i . One can consider that experiments developed for these species fall within the linear section of the adsorption isothenn ( = , Af C ). Using this condition, the k. adiq. m and K q m, groups can be calculated tlirough equations (7-9), (7-10) and (7-11), as reported in Table 7.3. Therefore k j can be calculated while circumventing the need for a prior definition of qi m-... 

The pjTous structure parameters obtained from nitrogen adsorption isothenns at 77 K by the cxs-plot method for the active carbons studied... 

An example of a phenol adsorption isothenn onto an activated carbon cloth is given in Fig. 3. Experimental data are modeled with the Langmuir and Freundlich equations. A graphical construction is presented the slope of the adsorption path is equal to - Vim according to the mass balance equation between fluid and solid phases. From a given Co, this graphical construction enables the final concentration Cf to be determined. 

We show in Figures 2 the adsorption isothenn of argon on graphitized thermal carbon black at a number of tenqieratures. The symbols in the figure are experimental data [13]. 

Adsorption isothenns of five gases at 293K for CMS determined from the volumetric experiments are shown in Fig. 1. Adsorption capacities of each gas are as follows Na, O2, Ar < CO CH4. 

Two porous materials relevant to cryosorption vacuum pumping were characterised by means of adsorption isothenns. Based on the example of the Langmuir isotherm, it is shown that the use of standard models may produce ambiguous results when tq)plied to non standard cases. 

This report also includes tliMretical work on the estimation of adsorption isothenn parameters and mass transfer rate coefficients, and the mathematical modeling of equilibrium-controlled and mass-transfer-controlled solvent sublation column operation in batch and continuous flow modes. 

Figure 4. Normalised PSDs fiom direct analysis (bars) and inversion of the adsorption isothenns of Figure 3 (lines) (a) N2, (b) CH4, and (c) CF4 and SFs isothenns (d) combining the PSDs of (b) and (c) within their respective windows of reliability, indicated by the dashed arrows.

Fig. 1. Nitrogen adsorption isotherms at 77 K. (A) and CO adsorption isothenns at 273 K (B) of the carbons studied.

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