High-efficiency CO2 separation using hybrid LDH-polymer membranes

• Published in: Nature communications Vol. 12; no. 1; p. 3069
• Main Authors: Xu, Xiaozhi, Wang, Jiajie, Zhou, Awu, Dong, Siyuan, Shi, Kaiqiang, Li, Biao, Han, Jingbin, O’Hare, Dermot
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 24.05.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 147/137; 639/301/357/1018; 639/638/298/923/1028; 639/638/298/923/966; Carbon dioxide; Channels; Construction; Gas separation; Humanities and Social Sciences; Hydroxides; Membrane permeability; Membranes; multidisciplinary; Permeability; Polydimethylsiloxane; Polymers; Science; Science (multidisciplinary); Selectivity; Self-assembly; Upper bounds
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-23121-z

Membrane-based gas separation exhibits many advantages over other conventional techniques; however, the construction of membranes with simultaneous high selectivity and permeability remains a major challenge. Herein, (LDH/FAS) n -PDMS hybrid membranes, containing two-dimensional sub-nanometre channels were fabricated via self-assembly of unilamellar layered double hydroxide (LDH) nanosheets and formamidine sulfinic acid (FAS), followed by spray-coating with a poly(dimethylsiloxane) (PDMS) layer. A CO 2 transmission rate for (LDH/FAS) 25 -PDMS of 7748 GPU together with CO 2 selectivity factors (SF) for SF(CO 2 /H 2 ), SF(CO 2 /N 2 ) and SF(CO 2 /CH 4 ) mixtures as high as 43, 86 and 62 respectively are observed. The CO 2 permselectivity outperforms most reported systems and is higher than the Robeson or Freeman upper bound limits. These (LDH/FAS) n -PDMS membranes are both thermally and mechanically robust maintaining their highly selective CO 2 separation performance during long-term operational testing. We believe this highly-efficient CO 2 separation performance is based on the synergy of enhanced solubility, diffusivity and chemical affinity for CO 2 in the sub-nanometre channels. Membrane-based gas separation exhibits many advantages over other conventional techniques but the construction of membranes with simultaneous high selectivity and permeability remains a major challenge. Here, the authors propose a layered double hydroxide (LDH)-polymer hybrid membrane, which shows improved CO 2 permselectivity.