Recovery of dilute aqueous acetone, butanol, and ethanol with immobilized calixarene cavities

Anthony B. Thompson, Rachel C. Scholes, Justin M Notestein

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Macrocyclic calixarene molecules were modified with functional groups of different polarities at the upper rim and subsequently grafted to mesoporous silica supports through a single Si atom linker. The resulting materials were characterized by thermogravimetric analysis, UV-visible spectroscopy, nitrogen physisorption, and solid-state NMR spectroscopy. Materials were then used to separate acetone, n-butanol, and ethanol from dilute aqueous solution, as may be useful in the recovery of fermentation-based biofuels. For the purpose of modeling batch adsorption isotherms, the materials were considered to have one strong adsorption site per calixarene molecule and a larger number of weak adsorption sites on the silica surface and external to the calixarene cavity. The magnitude of the net free energy change of adsorption varied from approximately 15 to 20 kJ/mol and was found to decrease as upper-rim calixarene functional groups became more electron-withdrawing. Adsorption appears to be driven by weak van der Waals interactions with the calixarene cavity and, particularly for butanol, minimizing contacts with solvent water. In addition to demonstrating potentially useful new sorbents, these materials provide some of the first experimental estimates of the energy of interaction between aqueous solutes and hydrophobic calixarenes, which have previously been inaccessible because of the insolubility of most nonionic calixarene species in water.

Original languageEnglish
Pages (from-to)289-297
Number of pages9
JournalACS Applied Materials and Interfaces
Volume6
Issue number1
DOIs
Publication statusPublished - Jan 8 2014

Fingerprint

Calixarenes
Butanols
Acetone
Butenes
Ethanol
Adsorption
Recovery
Functional groups
Silica
Molecules
Physisorption
Silicon Dioxide
Biofuels
Sorbents
Adsorption isotherms
Fermentation
Nuclear magnetic resonance spectroscopy
Free energy
Thermogravimetric analysis
Water

Keywords

  • adsorption
  • aqueous
  • biofuels
  • calixarenes
  • fermentation
  • silica

ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Recovery of dilute aqueous acetone, butanol, and ethanol with immobilized calixarene cavities. / Thompson, Anthony B.; Scholes, Rachel C.; Notestein, Justin M.

In: ACS Applied Materials and Interfaces, Vol. 6, No. 1, 08.01.2014, p. 289-297.

Research output: Contribution to journalArticle

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