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Glucose recovery from aqueous solutions by adsorption in metal-organic framework MIL-101: a molecular simulation study.

Gupta KM, Zhang K, Jiang J - Sci Rep (2015)

Bottom Line: Upon functionalization by -NH2 or -CH3 group, the steric hindrance in MIL-101 increases; consequently, the interactions between glucose and framework become less attractive, thus reducing the capacity and mobility of glucose.The presence of ionic liquid, 1-ethyl-3-methyl-imidazolium acetate, as an impurity reduces the strength of hydrogen-bonding between glucose and MIL-101, and leads to lower capacity and mobility.Upon adding anti-solvent (ethanol or acetone), a similar adverse effect is observed.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 117576, Singapore.

ABSTRACT
A molecular simulation study is reported on glucose recovery from aqueous solutions by adsorption in metal-organic framework MIL-101. The F atom of MIL-101 is identified to be the most favorable adsorption site. Among three MIL-101-X (X = H, NH2 or CH3), the parent MIL-101 exhibits the highest adsorption capacity and recovery efficacy. Upon functionalization by -NH2 or -CH3 group, the steric hindrance in MIL-101 increases; consequently, the interactions between glucose and framework become less attractive, thus reducing the capacity and mobility of glucose. The presence of ionic liquid, 1-ethyl-3-methyl-imidazolium acetate, as an impurity reduces the strength of hydrogen-bonding between glucose and MIL-101, and leads to lower capacity and mobility. Upon adding anti-solvent (ethanol or acetone), a similar adverse effect is observed. The simulation study provides useful structural and dynamic properties of glucose in MIL-101, and it suggests that MIL-101 might be a potential candidate for glucose recovery.

No MeSH data available.


Density profiles of glucose in glucose/water/MIL-101-X systems.The top illustrates a typical simulation snapshot at equilibrium (water molecules not shown).
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f2: Density profiles of glucose in glucose/water/MIL-101-X systems.The top illustrates a typical simulation snapshot at equilibrium (water molecules not shown).

Mentions: Upon the initiation of MD simulation, glucose molecules were observed to gradually move from solution to MIL-101-X. Figure S1 of the Supplementary Information shows the numbers of glucose adsorbed in MIL-101, MIL-101-NH2 and MIL-101-CH3 (systems 1–3) versus simulation time, and similar plots are shown in Figure S2 for systems 4–6 in the presence of IL, ethanol and acetone. Obviously, the numbers remain nearly constant after approximately 20 ns. The adsorption process can be visualized by a movie in the Supplementary Information. Figure 2 shows a typical simulation snapshot at equilibrium and the ensemble averaged density profiles of glucose in glucose/water/MIL-101-X systems. In each system, the maximum density is located between 7 and 16 nm, indicating glucose is adsorbed into the cages in MIL-101-X. Because the cages are not homogeneously distributed, thus the profile is not uniform. Overall, the density in MIL-101 is higher than in MIL-101-NH2 and MIL-101-CH3. The average numbers of adsorbed glucose molecules are 241.8 in MIL-101, 228.4 in MIL-101-NH2 and 228.5 in MIL-101-CH3. This reveals that the adsorption capacity of glucose in MIL-101 is reduced upon functionalization, as attributed to the reduced free volume or porosity in the presence of functional groups. Specifically, the porosity is 0.824 in MIL-101, and reduced to 0.795 in MIL-101-NH2 and MIL-101-CH327. The recovery efficacy of glucose is quantified by separation factor, defined as (Nad/Vad)/(Nw/Vw), where Nad and Nw are the numbers of glucose molecules in adsorbed phase and solution, Vad and Vw are the volumes of the two phases. In MIL-101, MIL-101-NH2 and MIL-101-CH3, the separation factors are 2.15, 1.81 and 1.79, respectively. Apparently, the separation factor drops upon functionalization.


Glucose recovery from aqueous solutions by adsorption in metal-organic framework MIL-101: a molecular simulation study.

Gupta KM, Zhang K, Jiang J - Sci Rep (2015)

Density profiles of glucose in glucose/water/MIL-101-X systems.The top illustrates a typical simulation snapshot at equilibrium (water molecules not shown).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525290&req=5

f2: Density profiles of glucose in glucose/water/MIL-101-X systems.The top illustrates a typical simulation snapshot at equilibrium (water molecules not shown).
Mentions: Upon the initiation of MD simulation, glucose molecules were observed to gradually move from solution to MIL-101-X. Figure S1 of the Supplementary Information shows the numbers of glucose adsorbed in MIL-101, MIL-101-NH2 and MIL-101-CH3 (systems 1–3) versus simulation time, and similar plots are shown in Figure S2 for systems 4–6 in the presence of IL, ethanol and acetone. Obviously, the numbers remain nearly constant after approximately 20 ns. The adsorption process can be visualized by a movie in the Supplementary Information. Figure 2 shows a typical simulation snapshot at equilibrium and the ensemble averaged density profiles of glucose in glucose/water/MIL-101-X systems. In each system, the maximum density is located between 7 and 16 nm, indicating glucose is adsorbed into the cages in MIL-101-X. Because the cages are not homogeneously distributed, thus the profile is not uniform. Overall, the density in MIL-101 is higher than in MIL-101-NH2 and MIL-101-CH3. The average numbers of adsorbed glucose molecules are 241.8 in MIL-101, 228.4 in MIL-101-NH2 and 228.5 in MIL-101-CH3. This reveals that the adsorption capacity of glucose in MIL-101 is reduced upon functionalization, as attributed to the reduced free volume or porosity in the presence of functional groups. Specifically, the porosity is 0.824 in MIL-101, and reduced to 0.795 in MIL-101-NH2 and MIL-101-CH327. The recovery efficacy of glucose is quantified by separation factor, defined as (Nad/Vad)/(Nw/Vw), where Nad and Nw are the numbers of glucose molecules in adsorbed phase and solution, Vad and Vw are the volumes of the two phases. In MIL-101, MIL-101-NH2 and MIL-101-CH3, the separation factors are 2.15, 1.81 and 1.79, respectively. Apparently, the separation factor drops upon functionalization.

Bottom Line: Upon functionalization by -NH2 or -CH3 group, the steric hindrance in MIL-101 increases; consequently, the interactions between glucose and framework become less attractive, thus reducing the capacity and mobility of glucose.The presence of ionic liquid, 1-ethyl-3-methyl-imidazolium acetate, as an impurity reduces the strength of hydrogen-bonding between glucose and MIL-101, and leads to lower capacity and mobility.Upon adding anti-solvent (ethanol or acetone), a similar adverse effect is observed.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, 117576, Singapore.

ABSTRACT
A molecular simulation study is reported on glucose recovery from aqueous solutions by adsorption in metal-organic framework MIL-101. The F atom of MIL-101 is identified to be the most favorable adsorption site. Among three MIL-101-X (X = H, NH2 or CH3), the parent MIL-101 exhibits the highest adsorption capacity and recovery efficacy. Upon functionalization by -NH2 or -CH3 group, the steric hindrance in MIL-101 increases; consequently, the interactions between glucose and framework become less attractive, thus reducing the capacity and mobility of glucose. The presence of ionic liquid, 1-ethyl-3-methyl-imidazolium acetate, as an impurity reduces the strength of hydrogen-bonding between glucose and MIL-101, and leads to lower capacity and mobility. Upon adding anti-solvent (ethanol or acetone), a similar adverse effect is observed. The simulation study provides useful structural and dynamic properties of glucose in MIL-101, and it suggests that MIL-101 might be a potential candidate for glucose recovery.

No MeSH data available.