CO2-selective zeolitic imidazolate framework membrane on graphene oxide nanoribbons: experimental and theoretical studies

Abstract

A CO₂-selective ZIF-type membrane was fabricated by growing a ZIF-8 layer on a graphene oxide nanoribbon (GONR)-coated polymeric substrate. Owing to the strong anchoring effect of GONRs to the ZIF-8 crystal, the pore window of the ZIF-8 layer can be tuned with a molecular cut-off range of 3.4–3.6 Å. The prepared membrane showed a CO₂ permeance of 7.8 × 10⁻⁹ mol m⁻² Pa⁻¹ s⁻¹ with a CO₂/CH₄ selectivity of 27, which surpassed the CO₂/hydrocarbon separation performance of most reported ZIF-type membranes and were comparable to those of ZIF-94 type membranes known to be effective for CO₂ extraction. Multiscale computational simulation demonstrated that the CO₂ selective permeation of the ZIF-8/GONR membrane was attributed to the low diffusivity of CH₄ in the rigid ZIF-8 framework. The obtained experimental and computational results illustrate that the pore-tuned ZIF-8 framework can be effectively used for CO₂ separation by adjusting the aperture size.