Handle URI:
http://hdl.handle.net/10754/597474
Title:
Adsorption of Water and Ethanol in MFI-Type Zeolites
Authors:
Zhang, Ke; Lively, Ryan P.; Noel, James D.; Dose, Michelle E.; McCool, Benjamin A.; Chance, Ronald R.; Koros, William J.
Abstract:
Water and ethanol vapor adsorption phenomena are investigated systematically on a series of MFI-type zeolites: silicalite-1 samples synthesized via both alkaline (OH -) and fluoride (F -) routes, and ZSM-5 samples with different Si/Al ratios as well as different charge-balancing cations. Full isotherms (0.05-0.95 activity) over the range 25-55 °C are presented, and the lowest total water uptake ever reported in the literature is shown for silicalite-1 made via a fluoride-mediated route wherein internal silanol defects are significantly reduced. At a water activity level of 0.95 (35 °C), the total water uptake by silicalite-1 (F -) was found to be 0.263 mmol/g, which was only 12.6%, 9.8%, and 3.3% of the capacity for silicalite-1 (OH -), H-ZSM-5 (Si/Al:140), and H-ZSM-5 (Si/Al:15), respectively, under the same conditions. While water adsorption shows distinct isotherms for different MFI-type zeolites due to the difference in the concentration, distribution, and types of hydrophilic sites, the ethanol adsorption isotherms present relatively comparable results because of the overall organophilic nature of the zeolite framework. Due to the dramatic differences in the sorption behavior with the different sorbate-sorbent pairs, different models are applied to correlate and analyze the sorption isotherms. An adsorption potential theory was used to fit the water adsorption isotherms on all MFI-type zeolite adsorbents studied. The Langmuir model and Sircar's model are applied to describe ethanol adsorption on silicalite-1 and ZSM-5 samples, respectively. An ideal ethanol/water adsorption selectivity (α) was estimated for the fluoride-mediated silicalite-1. At 35 °C, α was estimated to be 36 for a 5 mol % ethanol solution in water increasing to 53 at an ethanol concentration of 1 mol %. The adsorption data demonstrate that silicalite-1 made via the fluoride-mediated route is a promising candidate for ethanol extraction from dilute ethanol-water solutions. © 2012 American Chemical Society.
Citation:
Zhang K, Lively RP, Noel JD, Dose ME, McCool BA, et al. (2012) Adsorption of Water and Ethanol in MFI-Type Zeolites. Langmuir 28: 8664–8673. Available: http://dx.doi.org/10.1021/la301122h.
Publisher:
American Chemical Society (ACS)
Journal:
Langmuir
KAUST Grant Number:
KUS-I1-011-21
Issue Date:
12-Jun-2012
DOI:
10.1021/la301122h
PubMed ID:
22568830
Type:
Article
ISSN:
0743-7463; 1520-5827
Sponsors:
This material is based upon work supported by the Department of Energy under Award Number DE-FOA-0000096 and also supported by Algenol Biofuels. The authors thank Joshua Thompson and Megan Lydon for useful discussions on the synthesis of silicalite-1 using the fluoride mediated route. W. J. Koros thanks Award no. KUS-I1-011-21 made by King Abdullah University of Science and Technology (KAUST) for financial support.
Appears in Collections:
Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorZhang, Keen
dc.contributor.authorLively, Ryan P.en
dc.contributor.authorNoel, James D.en
dc.contributor.authorDose, Michelle E.en
dc.contributor.authorMcCool, Benjamin A.en
dc.contributor.authorChance, Ronald R.en
dc.contributor.authorKoros, William J.en
dc.date.accessioned2016-02-25T12:40:26Zen
dc.date.available2016-02-25T12:40:26Zen
dc.date.issued2012-06-12en
dc.identifier.citationZhang K, Lively RP, Noel JD, Dose ME, McCool BA, et al. (2012) Adsorption of Water and Ethanol in MFI-Type Zeolites. Langmuir 28: 8664–8673. Available: http://dx.doi.org/10.1021/la301122h.en
dc.identifier.issn0743-7463en
dc.identifier.issn1520-5827en
dc.identifier.pmid22568830en
dc.identifier.doi10.1021/la301122hen
dc.identifier.urihttp://hdl.handle.net/10754/597474en
dc.description.abstractWater and ethanol vapor adsorption phenomena are investigated systematically on a series of MFI-type zeolites: silicalite-1 samples synthesized via both alkaline (OH -) and fluoride (F -) routes, and ZSM-5 samples with different Si/Al ratios as well as different charge-balancing cations. Full isotherms (0.05-0.95 activity) over the range 25-55 °C are presented, and the lowest total water uptake ever reported in the literature is shown for silicalite-1 made via a fluoride-mediated route wherein internal silanol defects are significantly reduced. At a water activity level of 0.95 (35 °C), the total water uptake by silicalite-1 (F -) was found to be 0.263 mmol/g, which was only 12.6%, 9.8%, and 3.3% of the capacity for silicalite-1 (OH -), H-ZSM-5 (Si/Al:140), and H-ZSM-5 (Si/Al:15), respectively, under the same conditions. While water adsorption shows distinct isotherms for different MFI-type zeolites due to the difference in the concentration, distribution, and types of hydrophilic sites, the ethanol adsorption isotherms present relatively comparable results because of the overall organophilic nature of the zeolite framework. Due to the dramatic differences in the sorption behavior with the different sorbate-sorbent pairs, different models are applied to correlate and analyze the sorption isotherms. An adsorption potential theory was used to fit the water adsorption isotherms on all MFI-type zeolite adsorbents studied. The Langmuir model and Sircar's model are applied to describe ethanol adsorption on silicalite-1 and ZSM-5 samples, respectively. An ideal ethanol/water adsorption selectivity (α) was estimated for the fluoride-mediated silicalite-1. At 35 °C, α was estimated to be 36 for a 5 mol % ethanol solution in water increasing to 53 at an ethanol concentration of 1 mol %. The adsorption data demonstrate that silicalite-1 made via the fluoride-mediated route is a promising candidate for ethanol extraction from dilute ethanol-water solutions. © 2012 American Chemical Society.en
dc.description.sponsorshipThis material is based upon work supported by the Department of Energy under Award Number DE-FOA-0000096 and also supported by Algenol Biofuels. The authors thank Joshua Thompson and Megan Lydon for useful discussions on the synthesis of silicalite-1 using the fluoride mediated route. W. J. Koros thanks Award no. KUS-I1-011-21 made by King Abdullah University of Science and Technology (KAUST) for financial support.en
dc.publisherAmerican Chemical Society (ACS)en
dc.titleAdsorption of Water and Ethanol in MFI-Type Zeolitesen
dc.typeArticleen
dc.identifier.journalLangmuiren
dc.contributor.institutionGeorgia Institute of Technology, Atlanta, United Statesen
dc.contributor.institutionAlgenol Biofuels Inc., , United Statesen
kaust.grant.numberKUS-I1-011-21en

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