Henry's Law as a Limit for an Isotherm Model Based on a Statistical Mechanics Approach

Rocha, Milton Silva da; Iha, Koshun; Faleiros, Antônio Cândido; Corat, Evaldo José; Suárez-Iha, Maria Encarnación Vázquez

doi:10.1006/jcis.1998.5779

Cited by 29 publications

(7 citation statements)

References 4 publications

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“…The equations of these models and their linearised forms are shown in Table 4 (Silva da Rocha et al 1998;Behnamfard and Salarirad 2009;Rafatullah et al 2009;Khambhaty et al 2009). The Langmuir isotherm is an example of a favourable isotherm and is applicable under the following hypothesis: a uniform surface of the solid, uniform energies of adsorption on the surface, the absence of interaction between adsorbed molecules and adsorption in a single layer (no transmigration of the sorbate in the plane of the surface).…”

Section: Adsorption Isotherm Studiesmentioning

confidence: 99%

Use of Granular Bentonite in the Removal of Mercury (II), Cadmium (II) and Lead (II) from Aqueous Solutions

Fernández-Nava

Ulmanu

Anger

et al. 2010

Water Air Soil Pollut

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Granular bentonite has been assessed regarding its capacity to remove Hg(II), Cd(II) and Pb (II) from aqueous solutions. Sorption capacities, kinetics and the dependence of the sorption process on pH were determined. Fractional power, pseudofirst-order, pseudo-second-order and intra-particle diffusion equations were used to model the kinetics of metal adsorption. The pseudo-second-order model showed the best fit to experimental data. Different two-parameter sorption isotherm models (Langmuir, Freundlich, Temkin and Dubinin-Radushkevich) were used to fit the equilibrium data. Freundlich's isotherm model gave the best fit to experimental data. The selectivity of granular bentonite towards these metals is Pb(II)>Cd(II)>Hg(II). The adsorption capacities of granular bentonite towards the metals expressed in milligramme metal per gramme granular bentonite are 19.45, 13.05 and 1.7 for Pb(II), Cd(II) and Hg(II), respectively (for an initial concentration of 100 mg metal/L).

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Section: Adsorption Isotherm Studiesmentioning

confidence: 99%

Use of Granular Bentonite in the Removal of Mercury (II), Cadmium (II) and Lead (II) from Aqueous Solutions

Fernández-Nava

Ulmanu

Anger

et al. 2010

Water Air Soil Pollut

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“…Therefore, one theoretically expects a distribution in the “microscopic” Henry's regime . The Henry region represents the rudimental model between an adsorbate particle and the solid adsorbent surface and defines how much a fluid can be adsorbed on the surface or in the confined space of pores and how adsorption varies with temperature. − The Henry constants are obtained experimentally from the measurements of adsorption isotherms at various temperatures using either a volumetric or gravimetric method or from chromatography. The classical and statistical thermodynamics suggest that the Henry constant always exists at zero loading, from which one can easily calculate the isosteric heat of adsorption. , The Henry’s region is the low pressure and low uptake regime, where each gas molecule can explore the whole adsorbent surface independently and the gases in the adsorbed phase are most strongly attracted to the adsorption sites with the highest energies; that is, the adsorption energy (Δ H °) shows the maximum value in the Henry’s regime.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Insight of Physical Adsorption for a Single Component Adsorbent + Adsorbate System: II. The Henry Region

Chakraborty

Saha

et al. 2009

Langmuir

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The Henry coefficients of a single component adsorbent + adsorbate system are calculated from experimentally measured adsorption isotherm data, from which the heat of adsorption at zero coverage is evaluated. The first part of the papers relates to the development of thermodynamic property surfaces for a single-component adsorbent+adsorbate system (Chakraborty, A.; Saha, B. B.; Ng, K. C.; Koyama, S.; Srinivasan, K. Langmuir 2009, 25, 2204). A thermodynamic framework is presented to capture the relationship between the specific surface area (Ai) and the energy factor, and the surface structural and the surface energy heterogeneity distribution factors are analyzed. Using the outlined approach, the maximum possible amount of adsorbate uptake has been evaluated and compared with experimental data. It is found that the adsorbents with higher specific surface areas tend to possess lower heat of adsorption (DeltaH degrees) at the Henry regime. In this paper, we have established the definitive relation between Ai and DeltaH degrees for (i) carbonaceous materials, metal organic frameworks (MOFs), carbon nanotubes, zeolites+hydrogen, and (ii) activated carbons+methane systems. The proposed theoretical framework of Ai and DeltaH degrees provides valuable guides for researchers in developing advanced porous adsorbents for methane and hydrogen uptake.

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“…This formalism in interpreting E a as a minimum adsorption energy. Actually, is shown elsewhere (12).…”

Section: Introductionmentioning

confidence: 94%

“…Following the second approach an expression for the ad-The energetic heterogeneity has been described on several sorption isotherm was derived and presented as an extension approaches that are related to the considered adsorption of Freundlich's isotherm (12). In this derivation N(Q) was model.…”

Section: Introductionmentioning

confidence: 99%

The Influence of the Temperature on the Parameters of Extended Freundlich's Isotherm

Rocha

Iha

Faleiros

et al. 1998

Journal of Colloid and Interface Science

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Henry's Law as a Limit for an Isotherm Model Based on a Statistical Mechanics Approach

Cited by 29 publications

References 4 publications

Use of Granular Bentonite in the Removal of Mercury (II), Cadmium (II) and Lead (II) from Aqueous Solutions

Use of Granular Bentonite in the Removal of Mercury (II), Cadmium (II) and Lead (II) from Aqueous Solutions

Theoretical Insight of Physical Adsorption for a Single Component Adsorbent + Adsorbate System: II. The Henry Region

The Influence of the Temperature on the Parameters of Extended Freundlich's Isotherm

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