A High‐Performance N2‐Selective MXene Membrane with Double Selectivity Mechanism for N2/CH4 Separation

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2024-04, Vol.20 (14), p.e2309360-n/a
• Main Authors: Xing, Guangyu, Cong, Shenzhen, Wang, Bo, Qiao, Zhihua, Li, Qinghua, Cong, Chang, Yuan, Ye, Sheng, Menglong, Zhou, Yunqi, Shi, Fei, Ma, Jun, Pan, Yurui, Liu, Xinlei, Zhao, Song, Wang, Jixiao, Wang, Zhi
• Format: Article
• Language: English
• Subjects: double selectivity mechanism; Membrane separation; Membranes; Methane; MXenes; N2/CH4 separation; Natural gas; nitrogen; Purification; Reluctance; Selectivity; Separation; unsaturated metal sites
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202309360

Membrane‐based separation process for unconventional natural gas purification (mainly N2/CH4 separation) has attracted more attention due to its considerable economic benefits. However, the majority of separation membranes at this stage, particularly N2‐selective membranes, achieve the desired separation target by mainly relying on the diffusivity‐selectivity mechanism. To overcome the limitation of a single mechanism, 2D lamellar MXene membranes with a double selectivity mechanism are prepared to enhance N2 permeance and N2/CH4 selectivity via introducing unsaturated metal sites into MXene, which can form specific interactions with N2 molecules and enhance N2 permeation. The resulting membranes exhibit an inspiring N2/CH4 separation performance with an N2 permeance of 344 GPU and N2/CH4 selectivity of 13.76. The collaboration of the double selectivity mechanism provides a new idea for the development of a novel N2‐selective membrane for N2 removal and CH4 purification, which further broadens the application prospects of membrane separation technology in the field of unconventional natural gas purification. An N2‐selective MXene membrane with a double selectivity mechanism is prepared for N2/CH4 separation. The activated Cr clusters can realize adsorption preference reversal of N2 and CH4 and regulate the free spacing of adjacent MXene sheets, resulting in high N2 permeance and N2/CH4 selectivity.