Secondary-Assembled Defect-Free Mof Membrane Via Triple-Needle Electrostatic Atomization for Highly Stable and Selective Organics Permeation

Two-dimensional lamellar membranes featuring well-defined nanochannels hold great promise for efficient organics separation. However, the extensively existed microdefects within laminate architecture greatly impair separation efficiency and structure stability of membranes. Herein, defect-free metal-organic framework (MOF) lamellar membrane is facilely constructed by triple-needle electrostatic atomization technology. Specifically, one needle atomizes small-sized Cu-TCPP MOF nanosheets (TCPP = meso-tetra(4-carboxyphenyl)porphyrin) to build lamellar skeleton, and the other two needles meantime atomize Cu2+ and TCPP to secondary-assemble crystals among nanosheets. In this manner, these non-selective microdefects are subtly sutured by the regenerated crystals with identical chemical components, resulting in a defect-free MOF lamellar membrane with enhanced structural stability. Importantly, this novel secondary-assembly method highly enhances the separation efficiency and meanwhile keeps high organics permeation for MOF membrane, with rejection of 93.8% for Rose Bengal (1.2 nm) and acetone permeance of 86.9 L m–2 h–1 bar–1. In addition, the multipoint connection between nanosheets and crystals ensures excellent surface shearing and compaction resistance for MOF membrane, permitting high and steady operation performance for over 100 h. This secondary-assembly methodology by one-step process to construct defect-free and steady lamellar membrane provides a new avenue for the development of efficient separation membranes