275183 Molecular Screening of Alcohol and Polyol Adsorption Onto MFI-Type Zeolites

Wednesday, October 31, 2012: 9:36 AM
405 (Convention Center )
Ruichang Xiong1, Stanley I. Sandler2 and Dionisios G. Vlachos1, (1)Catalysis Center for Energy Innovation, Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, (2)Department of Chemical Engineering, University of Delaware, Newark, DE

Configurational-bias grand canonical Monte Carlo (CB-GCMC) simulations and expanded ensemble (EE)-CB-GCMC simulations were performed to obtain adsorption isotherms of alcohols and polyols onto MFI-type zeolites from the gas phase and aqueous solution. In adsorption from both phases, Henry’s constants and heats of adsorption at infinite dilution for straight-chain alcohols, diols and triols in silicalite-1 are found to increase, and the saturation loadings decrease with increasing carbon number. Adsorption of straight-chain alcohols is more favorable than that of branched-chain alcohols. Henry’s constants increase with increasing number of hydroxyl groups for gas-phase adsorption, but decrease for adsorption from aqueous solution due to the strong hydrophilic solvent effect of water. The location of the hydroxyls does not affect significantly the adsorption from aqueous solution but does so in gas-phase adsorption. The saturation pressures for gas-phase adsorption decrease by orders of magnitude from the alcohols to the triols. Non-framework cations increase the adsorption of the small alcohols by an order magnitude at low concentrations (<1 mg/mL), but result in only a factor of 2 increase for larger alcohols like butanol at low concentrations (<0.03 mg/mL), and then decrease the adsorption at higher concentrations. Overall, the simulated results are in reasonable agreement with available experimental data.

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See more of this Session: Molecular Simulation of Adsorption I
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