Despite the availability of chemistries to tailor the pore architectures of microporous polymer membranes for chemical separations, trade-offs in permeability and selectivity with functional group manipulations nevertheless persist, which ultimately places an upper bound on membrane performance. Here we introduce a new design strategy to uncouple these attributes of the membrane. Key to our success is the incorporation of phase-change metal-organic frameworks (MOFs) into the polymer matrix, which can be used to increase the solubility of a specific gas in the membrane, and thereby its permeability. We further show that it is necessary to scale the size of the phase-change MOF to nanoscopic dimensions, in order to take advantage of this effect in a gas separation. Our observation of an increase in solubility and permeability of only one of the gases during steady-state permeability measurements suggests fast exchange between free and chemisorbed gas molecules within the MOF pores. While the kinetics of this exchange in phase-change MOFs are not yet fully understood, their role in enhancing the efficacy and efficiency of the separation is clearly a compelling new direction for membrane technology.

Diamine-Appended Mg2(dobpdc) Nanorods as Phase-Change Fillers in Mixed-Matrix Membranes for Efficient CO2/N2 Separations

Maserati L.
Primo
;
2017

Abstract

Despite the availability of chemistries to tailor the pore architectures of microporous polymer membranes for chemical separations, trade-offs in permeability and selectivity with functional group manipulations nevertheless persist, which ultimately places an upper bound on membrane performance. Here we introduce a new design strategy to uncouple these attributes of the membrane. Key to our success is the incorporation of phase-change metal-organic frameworks (MOFs) into the polymer matrix, which can be used to increase the solubility of a specific gas in the membrane, and thereby its permeability. We further show that it is necessary to scale the size of the phase-change MOF to nanoscopic dimensions, in order to take advantage of this effect in a gas separation. Our observation of an increase in solubility and permeability of only one of the gases during steady-state permeability measurements suggests fast exchange between free and chemisorbed gas molecules within the MOF pores. While the kinetics of this exchange in phase-change MOFs are not yet fully understood, their role in enhancing the efficacy and efficiency of the separation is clearly a compelling new direction for membrane technology.
Maserati L.; Meckler S.M.; Bachman J.E.; Long J.R.; Helms B.A.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11585/856532
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