关键词: 金属-有机骨架, 分子筛分, 膜, 天然气, CO₂捕获

Abstract:

UTSA-280 is a typical molecular sieving metal-organic framework (MOF) for separating CO₂ from CH₄ or N₂, but the traditional solution-based synthesis method usually receives MOF particles with considerable size. Here an alternative mechanochemical way was used to fabricate small sized UTSA-280 particles, which was subsequently acted as filler materials in the polysulfone (PSf) based mixed matrix membranes (MMMs) for natural gas purification and CO₂ capture in flue gases. It shows that the introduction of UTSA-280 filler in the PSf matrix not only accelerates the transmission of CO₂ but also boosts the mixed gas separation factor of CO₂/CH₄ and CO₂/N₂. When the filler loading was 30%(mass) the CO₂/CH₄ and CO₂/N₂ separation factor were 56.39 and 53.17, respectively, and the CO₂ permeability was 18.61 Barrer, compared with pure membrane, the CO₂/CH₄ and CO₂/N₂ separation factor and CO₂ permeability showed 47.3%, 63.5% and 128.9% enhancement ratio, respectively, thus breaking the "trade-off" limitation. By introducing this specific MOF with molecular sieving character, the MOF based MMMs can improve the permeability of CO₂ as well as gas separation performance, which is of great significance to the purification of natural gas and the capture of CO₂ in flue gas.

Key words: metal-organic frameworks, molecular sieving, membrane, natural gas, CO₂ capture