Freundlich isotherm linear form

Figure 7.10 Application of Freundlich isotherm (linearized form) to the adsorption isotherms of glycine on black stone at pH 6.9 (a) sample 1 and (b) sample 2.

Another form that fits data from sediments known to contain black carbon (e.g., soot) uses a combination of a linear isotherm and a Freundlich isotherm (Accardi-Dey and Gschwend, 2002) ... 

Freundlich isotherm An equation for an adsorption isotherm in the form of Cads = Kf(Cso n)n (if n = 1, the distribution is linear, see Chapter 2 for details), which describes the distribution of a chemical species between an adsorbent and an associated solution under equilibrium conditions. Some adsorption isotherms are better described with the Langmuir isotherm. 

Can Brunauer s conclusion be reached by plotting the data according to linearized forms of the Langmuir, Temkin, and Freundlich isotherms Explain your answer. 

Freundlich The Freundlich isotherm was fitted to the data by expressing the equation in its linearized form,... 

Adsorption equilibrium data of SO2, NH3 and CO2 were analyzed by the linearized forms of the Langmuir and Freundlich equations (see Eqns. 2 and 4). The water vapour isotherm was analyzed by the linearized forms of the Dubinin-Astakhov equation (6), because of the above mentioned condensation phenomena. 

The Langmuir isotherm, in the form of Eq. (18.46), is generally more successful in interpreting the data than is the Freundlich isotherm if only a monolayer is formed. A plot of 6 versus p is shown in Fig. 18.16. At low pressures, Kp 1 and 6 = Kp, so that 9 increases linearly with pressure. At high pressures, Kp > 1, so that 0 1. The surface is nearly covered with a monomolecular layer at high pressures, so that change in pressure produces little change in the amount adsorbed. 

The Freundlich isotherm model takes the multilayer and heterogeneous adsorption into account. Its linearized form can be given as follows... 

This has the form of the Freundlich isotherm, which often empirically provides a good fit to adsorption data, especially in liquids, that cannot be adequately fit by a Langmuir isotherm. Using a linear dependence of on 9,... 

The results are commonly expressed in the form of a sorption isotherm or a plot of the concentration of chemical sorbed (jj,g/g) versus the concentration remaining in solution (jj,g/L). Sorption isotherms generally exhibit one of three characteristic shapes depending on the sorption mechanism. These isotherms are referred to as the Langmuir isotherm, the Freundlich isotherm, and the linear isotherm (a special case of the Freundlich isotherm). The reader is referred to ref 1 for more details on sorption isotherms. 

Free gel was added to definite concentrations of the MB solutions (2-20 mg/1) at room temperature and was noted for its adsorption. It is clear from Figure 13.3 that the dye adsorption increases sharply with an increase in the initial dye concentration. When Cq was reached at 5 ppm and 10 ppm, the was reached at 10.04 and 20.81 respectively, which were much higher than reported Qe values of other adsorbents (Table 13.3). Equilibrium adsorption isotherm is an important criterion to determine the mechanism of dye adsorption on hydrogel. The Langmuir and Freundlich models are widely used to examine the adsorption isotherms. Freundlich isotherm models are based on the assumption that the surface of the adsorbent is not homogeneous. The experimental data in Figure 13.3 was also analyzed with the Freundlich isotherm model, which describes a heterogeneous system with multilayer adsorption. The linear form of Freundlich isotherm equation... 

The FreundUch isotherm by itself is not widely used to describe adsorption in zeoUtes. There are a handful of isotherms, for example, O2 on Type A or X can often be fit to the Freundlich form owing to the small deviations from linearity that occur in the isotherm. This estimator has the mathematical form ... 

In this section, we will discuss PVA-Iodine complexes which are formed at high iodine concentrations of soaking. Figure 22 shows the iodine sorption isotherm of a PVA film, obtained by soaking in iodine-KI solutions at 20 °C. The data in Fig. 22 apparently satisfy a Freundlich relation i.e. InQ increases linearly with InC. At 50 wt % sorption, the distribution coefficient is about 6 which is defined as the ratio of iodine concentration per water in a swollen PVA film to that of the soaking solution. This large distribution coefficient is due to the iodine sorption in the crystalline phase as well as in the amorphous phase. 

Modified Freundlich sorption models were developed to describe sorption in heterogeneous geosorbents containing both NOM and carbonaceous materials. Composite or distributed reactivity models (DRM) were introduced [28] and applied in a manner which combines the linear partitioning (absorption) part with the nonlinear adsorption part [26, 27, 31, 32]. The overall sorption isotherm can be described in the form of ... 

---