Application of a group contribution method for predicting adsorbability on activated carbon

Chitra, S.; Govind, Rakesh

doi:10.1002/aic.690320122

Cited by 12 publications

(7 citation statements)

References 2 publications

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“…This method is widely used in chemical engineering thermodynamics for estimating a variety of pure component properties such as liquid densities, heat capacities and critical constants for organic compounds. It has also been used for predicting adsorbability on activated carbon [3]. BACKGROUND Several studies have attempted to correlate some physicochemical or structural property of a *To whom correspondence may be addressed.…”

Section: Ntroductionmentioning

confidence: 99%

Development of quantitative structure‐activity relationships for predicting biodegradation kinetics

Desai

Govind

Tabak

1990

Enviro Toxic and Chemistry

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Section: Ntroductionmentioning

confidence: 99%

Development of quantitative structure‐activity relationships for predicting biodegradation kinetics

Desai

Govind

Tabak

1990

Enviro Toxic and Chemistry

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“…COSMO-RS employs density functional theory calculations to determine a polarity profile on the molecular surface as a basis for a computation of molecular interactions. Chitra and Govind (1986) developed a group contribution model to calculate the Freundlich parameters K and n of aliphatic adsorptives. The thermodynamic model assumes an ideal liquid phase.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of aromatic trace compounds from organic solvents on activated carbons—experimental results and modeling of adsorption equilibria

et al. 2012

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Liquid phase adsorption is an important process for the removal of trace compounds from liquid matrices. Until today, research on liquid phase adsorption is less substantial than work on other thermal separation processes. The description of relevant mechanisms and interactions is difficult mainly because of lacking experimental data. This paper presents extensive isotherm measurements for the adsorption of organic trace compounds from organic solvents on activated carbons. A systematic variation of molecular structure of adsorptives and solvents enabled the identification of main structural factors dominating adsorption in these systems. The factors are polarity, extension and density of π electrons and sterical complexity. An analysis of the measured isotherms revealed incremental effects of functional groups and structural elements being characteristic for the adsorption capacities on activated carbons. Three consecutive empirical prediction models of adsorption equilibria are developed and compared. The empirical Freundlich equation appeared to be best suited for fitting the experimental data. The models apply an incremental concept permitting the calculation of adsorption isotherms on the basis of the structural increments of solvent and adsorptive molecules. The three models have a different extent of underlying data, a different number of parameters and a different range of application. The experimental data are predicted with satisfying accuracy for many engineering applications. The most sophisticated model has the most extensive range of application and manages on the smallest number of parameters.

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“…In the case of dilute solutions and sometimes even at higher concentrations, several isotherms actually applied for gas adsorption are used to calculate liquid-phase adsorption. , Aside from empirical equations, models with interaction parameters (e.g., Langmuir−Freundlich) or association constants were developed in order to fit the experimental data. Some approaches make use of the classical formulation of phase equilibrium for adsorption as introduced by Gibbs in combination with activity coefficient models …”

Section: Introductionmentioning

confidence: 99%

“…Some approaches make use of the classical formulation of phase equilibrium for adsorption as introduced by Gibbs in combination with activity coefficient models. 4 However, the above-mentioned equations may only be used for correlations while they lack the possibility to predict surface excess isotherms. Simulation methods like the Monte Carlo 5 method may offer the possibility to predict surface excess isotherms but are rarely used until now, particularly since they are limited to simple systems with respect to the pore shape and the adsorbed species.…”

Section: Introductionmentioning

confidence: 99%

Correlation and Prediction of Liquid-Phase Adsorption on Zeolites Using Group Contributions Based on Adsorbate−Solid Solution Theory

et al. 1999

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Both correlation as well as prediction of experimental data for the adsorption of various binary liquid mixtures of alkanes and alkenes on NaX at different temperatures are presented. The theoretical background is based on the adsorbate−solid solution theory which conceives the adsorbed phase to be a mixture of the adsorbed species (adsorbate) and the adsorbent as an additional component. With the introduction of the Gibbs excess energy GE* for this hypothetical mixture, activity coefficients and composition of the adsorbed phase may be calculated. The Gibbs excess energy and thus the activity coefficients of the adsorbed species depend strongly on the energetic heterogeneity of the solid surface which may be described by use of so-called group contribution models. These approaches, until now widely applied to predict fluid-phase equilibrium, are derived from statistical thermodynamics and take into account the energetic interactions between the respective components. For the application of this approach on thermodynamics of adsorption zeolites have to be divided into different functional groups such as SiO2, AlO2 -, and the respective cations. The interaction energies between these active sites and the functional groups of the adsorbed liquid molecules represent fundamental parameters of activity coefficient models based on group contributions such as UNIFAC. These parameters were determined by fitting four different adsorption systems. With the fitted values, six other systems were predicted. Both correlation and prediction include adsorption data at different temperatures. All calculations show excellent results with a mean relative deviation of 4.2% for the correlation and a mean deviation in the range of 8−17% for the predictions.

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Application of a group contribution method for predicting adsorbability on activated carbon

Cited by 12 publications

References 2 publications

Development of quantitative structure‐activity relationships for predicting biodegradation kinetics

Development of quantitative structure‐activity relationships for predicting biodegradation kinetics

Adsorption of aromatic trace compounds from organic solvents on activated carbons—experimental results and modeling of adsorption equilibria

Correlation and Prediction of Liquid-Phase Adsorption on Zeolites Using Group Contributions Based on Adsorbate−Solid Solution Theory

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