Adsorption of Water and Butanol in Silicalite-1 Film Studied with in-situ ATR-FTIR Spectroscopy

• Biobutanol produced by, e.g., acetone–butanol–ethanol (ABE) fermentation is a promising alternative to petroleum-based chemicals as, e.g., solvent and fuel. Recovery of butanol from dilute fermentation broths by hydrophobic membranes and adsorbents has been identified as a promising route. In this work, the adsorption of water and butanol vapor in a silicalite-1 film was studied using in situ attenuated total reflectance–Fourier transform infrared (ATR–FTIR) spectroscopy to better understand the adsorption properties of silicalite-1 membranes and adsorbents. Single-component adsorption isotherms were determined in the temperature range of 35–120 °C, and the Langmuir model was successfully fitted to the experimental data. The adsorption of butanol is very favorable compared to that of water. When the silicalite-1 film was exposed to a butanol/water vapor mixture with 15 mol % butanol (which is the vapor composition of an aqueous solution containing 2 wt % butanol, a typical concentration in an ABE fermentation broth, i.e., the composition of the gas obtained from gas stripping of an ABE broth) at 35 °C, the adsorption selectivity toward butanol was as high as 107. These results confirm that silicalite-1 quite selectively adsorbs hydrocarbons from vapor mixtures. To the best of our knowledge, this is the first comprehensive study on the adsorption of water and butanol in silicalite-1 from vapor phase.

• Bio-butanol produced by e.g. acetone–butanol–ethanol (ABE) fermentation is a promising alternative to petroleum-based chemicals as e.g. solvent and fuel. Recovery of butanol from dilute fermentation broths by hydrophobic membranes and adsorbents has been identified as a promising route. In this work, the adsorption of water and butanol vapor in a silicalite-1 film was studied using in-situ ATR-FTIR spectroscopy in order to better understand the adsorption properties of silicalite-1 membranes and adsorbents. Single component adsorption isotherms were determined in the temperature range of 35-120°C and the Langmuir model was successfully fitted to the experimental data. The adsorption of butanol is very favorable compared to that of water. When the silicalite-1 film was exposed to a butanol/water vapor mixture with 15 mol% of butanol (which is the vapor composition of an aqueous solution containing 2 wt% of butanol, a typical concentration in an ABE fermentation broth, i.e. the composition of the gas obtained from gas stripping of an ABE broth) at 35 °C, the adsorption selectivity towards butanol was as high as 107. These results confirm that silicalite-1 quite selectively adsorbs hydrocarbons from vapor mixtures.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik -- Kemiska processer (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering -- Chemical Process Engineering (hsv//eng)

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Chemical Technology

Kemisk teknologi

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