Covalent Post‐Functionalization of Zeolitic Imidazolate Framework ZIF‐90 Membrane for Enhanced Hydrogen Selectivity

MOF constrictor: Covalent modification of a ZIF-90 membrane was achieved by imine condensation of the aldehyde groups of the metal–organic framework (MOF) linker by ethanolamine (see picture). The modification leads to constriction of the pore apertures and prevents unselective permeation through defect pores, thus improving gas separation performance. For a H2/CO2 mixture, selectivity can be increased from 7.3 to 62.5.