Mixed Matrix Composite Membranes with MOF-protruding Structure for
Efficient CO2 Separation
Abstract
Mixed matrix composite membranes (MMCMs) hold great potential to realize
efficient CO2 removal from natural gas. However, the reduction of
separation performance arising from the interfacial defects, significant
plasticization and aging effect in the thin films severely limit their
application. Herein, we fabricated a series of polyimide MMCMs with
MOF-protruding structure wherein amino-functionalized ZIF-8 nanocrystals
nearly penetrate the thin selective layer. Through engineering the
interfacial interactions, e.g., covalent or hydrogen bondings, we
successfully fabricated defect-free MMCMs with the thickness ranging
from 140 to 280 nm. The stronger interfacial interactions eliminate the
interfacial defects and restrict the mobility of polymer chains under
high pressure. Accordingly, the MMCM displays a high CO2 permeance of
778 GPU and a CO2/CH4 selectivity of 34 with significantly improved
resistance to plasticization and aging. Considering the superior
performance, we anticipate our work could provide guidelines on
designing advanced MMMs to tackle critical separations.