One-Step Synthesis of Ultrathin Zeolitic Imidazole Framework-8 (ZIF-8) Membrane on Unmodified Porous Support via Electrophoretic Deposition

Abstract

Metal–organic frameworks (MOFs) are regarded as the next-generation, disruptive membrane materials, yet the straightforward fabrication of ultrathin MOF membranes on an unmodified porous support remains a critical challenge. In this work, we proposed a facile, one-step electrophoretic deposition (EPD) method for the growth of ultrathin zeolitic imidazole framework-8 (ZIF-8) membranes on a bare porous support. The crystallinity, morphology and coverage of ZIF-8 particles on support surface can be optimized via regulating EPD parameters, yet it is still difficult to ensure the integrity of a ZIF-8 membrane with the constant voltage mode. In contrast, the constant current mode is more beneficial to the growth of a defect-free ZIF-8 membrane due to the steady migration rate of colloid particles toward the electrode. With a current of 0.65 mA/cm2 and deposition time of 60 min, a 300 nm thick ZIF-8 membrane was obtained, which exhibits a CO2 permeance of 334 GPU and a CO2/CH4 separation factor of 8.8, evidencing the defect-free structure.

Polymer-Infiltrated Metal–Organic Frameworks for Thin-Film Composite Mixed-Matrix Membranes with High Gas Separation Properties

“…Metal–organic frameworks (MOFs) are considered next-generation porous materials suitable for gas separation and capture because of their high surface area, tunable porosity, tailorable pore size, and functionality through the combination of various organic linkers and metal clusters [ 9 , 10 ]. Additionally, the ability to control the particle size of MOFs have a great advantage for the MMMs fabrication [ 10 , 11 ].…”