Enhanced CO2 separation in membranes with anion-cation dual pathways

Abstract
The factors contributing to the water-facilitated CO2 capture in membranes are investigated. Since CO2 transports through such hydrated membrane mainly in the form of bicarbonate, there is a pressing need for exploring the ionic transport mechanism. Herein, a series of composite charged membranes comprising a negatively charged polymer matrix and positively charged filler is proposed. For that, polymer brushes bearing imidazolium cations are grafted on graphene oxide and then dispersed in sulfonated poly (ether ether ketone) (SPEEK). Compared with the pristine SPEEK membranes, a significant enhancement in both CO2 permeability and CO2/N2 selectivity is observed. The encouraging results are discussed considering proton conductivity and bicarbonate diffusivity. More interestingly, the membranes show simultaneously higher CO2 permeability and CO2/N2 selectivity when the operating pressure or temperature are increased, supporting the occurrence of ionic transport mechanism arising from the unique anion-cation dual pathways at the polymer-filler interface.

Citation
Yan, Z., Zhang, M., Shi, F., Zhu, B., Liu, M., Wang, S., … Nunes, S. P. (2020). Enhanced CO2 separation in membranes with anion-cation dual pathways. Journal of CO2 Utilization, 38, 355–365. doi:10.1016/j.jcou.2020.02.016

Acknowledgements
The study was financially supported by National Natural Science Foundation of China (21878277 and 21506196), Natural Science Foundation of Henan province (182300410268), China Postdoctoral Science Foundation (2015M570633 and 2017T100538), and Outstanding Young Talent Research Fund of Zhengzhou University (1521324002) and King Abdullah University of Science and Technology (KAUST), Saudi Arabia. We also gratefully acknowledge the financial support from China Scholarship Council, and the instrument support from Center of Advanced Analysis & Computational Science, Zhengzhou University.

Publisher
Elsevier BV

Journal
Journal of CO2 Utilization

DOI
10.1016/j.jcou.2020.02.016

Additional Links
https://linkinghub.elsevier.com/retrieve/pii/S2212982019313186

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