The increasing importance of membrane-based gas separation processes necessitates the development of novel materials with enhanced permeability and selectivity. Polymers of Intrinsic Microporosity (PIMs) are promising candidates due to their rigid and highly contorted polymer backbone [1], which causes a high free volume. The latter confers to PIMs a very high permeability, while the backbone rigidity causes a high size selectivity. Since the introduction of archetypal PIM-1 [2], many different PIMs were synthesized, with different backbones [3] and/or functional groups [4], to improve their properties. Here, we present a study on modified PIM-1 with amine functional groups, which enhance the CO2 affinity. The original study [5] demonstrated that the amine-introduction leads to an unexpected reduction of the CO2 permeability, and time-lag analysis with single gases revealed a strong decrease of the CO2 diffusion coefficient with respect to the other gases. In the present paper we show via mixed gas analysis that the enhanced CO2-philicity increases the CO2/N2 and CO2/CH4 selectivity due to competitive sorption. CO2 preferentially interacts with the amine groups, hindering the transport of the other species in the membrane. Molecular dynamics simulations, a powerful tool to investigate the free volume distribution and the molecular structure of the polymers [6], will give a molecular insight into the experimental results. A novel method for experimental analysis of mixed gas diffusivity is also presented. Acknowledgements: This research received funding from the EU's Seventh Framework Program, GA 608490, project M4CO2. References [1] McKeown, N.B.; Budd, P.M., Macromolecules, 2010, 43, 5163-5176 [2] Budd, P. M. et al., Chem. Commun., 2004, 10, 230-231 [3] Carta, M. et al., Science, 2013, 339, 303-307 [4] Du, N. et al, Nat. Mater., 2011, 10, 372-375 [5] Mason, C. R. et al., Macromolecules, 2014, 47, 1021-1029 [6] Tocci, E. et al, Macromolecules, 2014, 47, 7900-7916
Increasing the selectivity of Polymers of Intrinsic Microporosity by competitive sorption.
Alessio Fuoco;Carmen Rizzuto;Marcello Monteleone;Elisa Esposito;Elena Tocci;Lidietta Giorno;
2017
Abstract
The increasing importance of membrane-based gas separation processes necessitates the development of novel materials with enhanced permeability and selectivity. Polymers of Intrinsic Microporosity (PIMs) are promising candidates due to their rigid and highly contorted polymer backbone [1], which causes a high free volume. The latter confers to PIMs a very high permeability, while the backbone rigidity causes a high size selectivity. Since the introduction of archetypal PIM-1 [2], many different PIMs were synthesized, with different backbones [3] and/or functional groups [4], to improve their properties. Here, we present a study on modified PIM-1 with amine functional groups, which enhance the CO2 affinity. The original study [5] demonstrated that the amine-introduction leads to an unexpected reduction of the CO2 permeability, and time-lag analysis with single gases revealed a strong decrease of the CO2 diffusion coefficient with respect to the other gases. In the present paper we show via mixed gas analysis that the enhanced CO2-philicity increases the CO2/N2 and CO2/CH4 selectivity due to competitive sorption. CO2 preferentially interacts with the amine groups, hindering the transport of the other species in the membrane. Molecular dynamics simulations, a powerful tool to investigate the free volume distribution and the molecular structure of the polymers [6], will give a molecular insight into the experimental results. A novel method for experimental analysis of mixed gas diffusivity is also presented. Acknowledgements: This research received funding from the EU's Seventh Framework Program, GA 608490, project M4CO2. References [1] McKeown, N.B.; Budd, P.M., Macromolecules, 2010, 43, 5163-5176 [2] Budd, P. M. et al., Chem. Commun., 2004, 10, 230-231 [3] Carta, M. et al., Science, 2013, 339, 303-307 [4] Du, N. et al, Nat. Mater., 2011, 10, 372-375 [5] Mason, C. R. et al., Macromolecules, 2014, 47, 1021-1029 [6] Tocci, E. et al, Macromolecules, 2014, 47, 7900-7916I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
