Tailoring microenvironment of adsorbents to achieve excellent CO2 uptakes from wet gases

• Published in: AIChE journal Vol. 66; no. 11
• Main Authors: Jin, Meng‐Meng, Li, Yu‐Xia, Gu, Chen, Liu, Xiao‐Qin, Sun, Lin‐Bing
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.11.2020; American Institute of Chemical Engineers
• Subjects: Adsorbents; Adsorption; adsorption/gas; Carbon dioxide; Carbon sequestration; Continuous flow; environmental engineering; Flow stability; gas purification; Gases; Hydrophobicity; Polydimethylsiloxane; Relative humidity; surface chemistry/physics
• ISSN: 0001-1541; 1547-5905
• DOI: 10.1002/aic.16645

Due to the excellent adsorption capacity on CO2, Mg‐MOF‐74 is highly potential for carbon capture. However, the practical application is seriously hindered by the poor hydrolytic stability of Mg‐MOF‐74 even towards trace of moisture. Here we report a strategy by adjusting the microenvironment of Mg‐MOF‐74 from hydrophilic to superhydrophobic by coating polydimethylsiloxane (PDS, yielding M74@P), which markedly enhances the hydrolytic stability. Mg‐MOF‐74 is degraded obviously upon exposure to humid atmosphere (75% relative humidity) for 7 days, while M74@P retains its structure well even after 1 year. The dynamic breakthrough results show that the optimized M74@P sample can capture 6.65 mmol g−1 CO2 from wet CO2/N2 mixtures after 100 cycles, which is superior to Mg‐MOF‐74 (1.17 mmol g−1) and most reported adsorbents under comparable conditions (continuous flow adsorption from wet gases). The excellent adsorption capacity and hydrolytic stability make the present adsorbents highly promising for practical applications in carbon capture.