Adsorption studies of n-Olefin/n-paraffin mixtures on X- and Y-zeolites. I. Comparison of liquid phase and vapor phase adsorption of hexane-1 and n-hexane on NaX-zeolite

Intracrystalline self-diffusion coefficients were measured by pulsed field gradient (PFG) NMR for single components and binary mixtures of CF(4) and various hydrocarbons in large-crystal NaX zeolites. A short-time diffusion model was used to obtain the unrestricted intracrystalline self-diffusivities by extrapolating to zero diffusion time, when no molecules can leave the crystal during the measurement. The results were used to test a theoretical model from Skoulidas, Sholl, and Krishna for predicting diffusion coefficients of mixtures in zeolites from single-component data. The predicted binary self-diffusivities are consistent with those directly measured in PFG NMR mixture experiments, thus providing an experimental validation of the model.

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“… a s.c. = supercage. b Reference . c Reference . d From molecular simulation. e Reference . f Reference . g Reference . …”

Section: Resultsmentioning

confidence: 99%

Self-Diffusion Studies of Binary Mixtures in NaX Zeolites Using Pulsed Field Gradient NMR and a Maxwell−Stefan Model

Zhao

Snurr

2009

J. Phys. Chem. A

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“…For the calculations adsorption equilibrium data of different binary mixtures of alkanes and alkenes on NaX were taken from literature. − For the zeolite the molar weight has been estimated from the structural formula according to eq 40 ( M = 13 418 g/mol). All systems have been calculated taking into consideration the nonideality of the bulk phase by calculating the respective activity coefficients with modified UNIFAC.…”

Section: Calculation and First Resultsmentioning

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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“…In this way, the separation can be achieved at ambient temperature. Due to size-selective adsorption characteristics, different forms of zeolite and molecular sieves have gained considerable interest towards their industrial applications [1] for the separation of light olefin/paraffin mixtures [2], glucose-fructose mixtures [3], isomer separation [4,5], breaking azeotropes [6], separation of aromatics for the purpose of purification of chemicals [7], and so forth. In addition to various forms of zeolite, polymeric adsorbents and advanced materials containing metal-organic framework (MOF) have been developed for adsorptive separation of aliphatic and aromatic isomers [8].…”

Section: Applications Of Adsorption In Separation and Purificationmentioning

confidence: 99%

“…Continuous separations of olefin/paraffin mixtures are of high demand in chemical industries. Herden and his coresearchers have extensively studied the separation of olefin/paraffin mixtures using different modified forms of X-and Y-type zeolites [2,9,10]. The studies revealed that X-zeolites (Si/Al ratio 1.3) are more appropriate for olefin/paraffin separation.…”

Section: Applications Of Adsorption In Separation and Purificationmentioning

confidence: 99%

Separation Strategies for Processing of Dilute Liquid Streams

Mandal

Kulkarni

2011

International Journal of Chemical Engineering

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Processing of dilute liquid streams in the industries like food, agro-, biotechnology, pharmaceuticals, environment, and so forth needs special strategy for the separation and purification of the desired product and for environment friendly disposal of the waste stream. The separation strategy adopted to achieve the goal is extremely important from economic as well as from environmental point of view. In the present paper we have reviewed the various aspects of some selected universal separation strategies such as adsorption, membrane separation, electrophoresis, chromatographic separation, and electroosmosis that are exercised for processing of dilute liquid streams.

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Adsorption studies of n-Olefin/n-paraffin mixtures on X- and Y-zeolites. I. Comparison of liquid phase and vapor phase adsorption of hexane-1 and n-hexane on NaX-zeolite

Cited by 22 publications

References 5 publications

Self-Diffusion Studies of Binary Mixtures in NaX Zeolites Using Pulsed Field Gradient NMR and a Maxwell−Stefan Model

Self-Diffusion Studies of Binary Mixtures in NaX Zeolites Using Pulsed Field Gradient NMR and a Maxwell−Stefan Model

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

Separation Strategies for Processing of Dilute Liquid Streams

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