Enhancing hydrophobicity via core-shell metal organic frameworks for high-humidity flue gas CO2 capture

Developing metal-organic framework (MOF) materials with the moisture-resistant feature is highly desirable for CO2 capture from highly humid flue gas. In this work, a new core-shell MOF@MOF composite using Mg-MOF-74 with high CO2 capture capacity as a functional core and hydrophobic zeolitic imidazolate framework-8 (ZIF-8) as a protective shell is fabricated by the epitaxial growth method. Experimental results show that the CO2 adsorption performance of the core-shell structured Mg-MOF74@ZIF-8 composites from water-containing flue gas is enhanced along with their improved hydrophobicity. The dynamic breakthrough results show that the Mg-MOF-74@ZIF-8 with three assembled layers (Mg-MOF-74@ZIF-8-3) can capture 3.56 mmol center dot g(-1) CO2 from wet CO2/N-2 (V-CO2 : V-N2 = 15:85) mixtures, which outperforms Mg-MOF-74 (0.37 mmol center dot g(-1)) and most of the reported physisorbents. (c) 2023 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.