Moisture-tolerant diamine-appended metal–organic framework composites for effective indoor CO2 capture through facile spray coating

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2022-04, Vol.433, p.133856, Article 133856
• Main Authors: Seok Chae, Yun, Park, Sookyung, Won Kang, Dong, Won Kim, Dae, Kang, Minjung, San Choi, Doo, Hyeak Choe, Jong, Seop Hong, Chang
• Format: Article
• Language: English
• Subjects: Hydrophobicity; Indoor carbon dioxide capture; Metal-organic framework composites; MOF coating
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2021.133856

[Display omitted] •A novel method for coating of epn-Mg2(dobpdc)@SBS composites was developed.•The composites showed a significant CO2 working capacity with full recyclability.•Facile, generally applicable coating route with the composite ink was demonstrated.•The coated materials exhibited excellent recycable working capacity.•Long-term durability under realistic indoor CO2 conditions was obtained. Reducing the concentration of indoor carbon dioxide (CO2) to an acceptable safe level of 1,000 ppm is an important issue because a high level of CO2 in closed spaces causes lethargy and fatigue. Although diamine-functionalized metal–organic framework (MOF) adsorbents with high CO2 capacities under indoor air conditions are available, the moisture-induced degradation of MOFs and their shaping remains a challenge for practical applications. Herein, we report the fabrication of epn-functionalized Mg2(dobpdc) composites, which proceeded by mixing with a polystyrene-block-polybutadiene-block-polystyrene (SBS) hydrophobic polymer (epn = 1-ethylpropane-1,3-diamine; dobpdc4− = 4,4′-dioxido-3,3′-biphenyldicarboxylate). The composites were successfully shaped in the form of membranes with different amounts of MOF (epn-MOFX@SBS; X  = 60–80 wt%). Specifically, epn-MOF80@SBS exhibited a significant CO2 adsorption of 2.8 mmol g−1 at 1,000 ppm with recyclable working capacity. The composites were further coated on the surfaces of different supports, such as a Ti mesh, an air filter, and granular activated carbon via a facile and simple spraying method. The experimental conditions were 1,000 ppm CO2 and 60% relative humidity in a 50-L chamber; the coated materials displayed invariant CO2 removal performances over 10 cycles and even after 7 days of exposure. The recyclable and long-term CO2 adsorption capacities demonstrate that the MOF-polymer composites and their coating on various supports provide a useful and effective route for indoor CO2 capture under realistic conditions.