Biofuel purification in GME zeolitic–imidazolate frameworks: From ab initio calculations to molecular simulations |
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Authors: | Kang Zhang Krishna M Gupta Yifei Chen Jianwen Jiang |
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Affiliation: | Dept. of Chemical and Biomolecular Engineering, National University of Singapore, Kent Ridge, Singapore |
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Abstract: | A multiscale modeling study is reported on the adsorption of ethanol/water in five zeolitic–imidazolate frameworks (ZIFs) for biofuel purification. The ZIFs (ZIF‐68, ?69, ?78, ?79, and ?81) have isoreticular Gmelinite topology but differ in organic linkers. The simulated adsorption isotherms of ethanol and water in ZIF‐68 agree fairly well with experimental data. At a low pressure, ZIF‐78 exhibits the highest uptake due to strong hydrogen‐bonding between ?NO2 groups and adsorbates. The heats of adsorption at infinite dilution largely follow the trend of binding energies estimated from ab initio calculations. At a high pressure, the uptake is governed primarily by free volume but also affected by hydrogen‐bonding. Among the five ZIFs, ZIF‐79 with hydrophobic ?CH3 groups shows the highest adsorptive selectivity for ethanol/water mixtures. This study provides microscopic insights into the adsorption and separation of ethanol/water in ZIFs, and would facilitate the development of new ZIFs for biofuel purification. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2763–2775, 2015 |
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Keywords: | biofuel zeolitic– imidazolate frameworks modeling adsorption separation |
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