The effect of pore sizes on D2/H2 separation conducted by MOF-74 analogues

• Published in: Inorganic chemistry frontiers Vol. 9; no. 8; pp. 1674 - 1680
• Main Authors: Li, Liqiong, Ji, Chunqing, Wang, Wenjing, Wu, Fan, Yan-Xi, Tan, Yuan, Daqiang
• Format: Journal Article
• Language: English
• Published: London Royal Society of Chemistry 21.02.2022
• Subjects: Diffusion rate; Hydrogen isotopes; Inorganic chemistry; Metal-organic frameworks; Mixtures; Pore size; Separation
• ISSN: 2052-1545; 2052-1553
• DOI: 10.1039/d2qi00156j

Four stable MOF-74 analogues, namely Ni2(dobdc), Ni2(dobpdc), Ni2(olz) and Ni2(dotpdc), possessing abundant open metal sites (OMSs) and honeycomb channels with pore sizes ranging from 1.0 to 2.6 nm, were used to research the effects of the pore size on D2/H2 separation from the hydrogen isotope mixture through dynamic column breakthrough experiments. With respect to consideration of the chemical affinity quantum sieving (CAQS) effect and the competitive adsorption between Ne and hydrogen isotope in (H2/D2/Ne: 1/1/98) and (H2/D2/Ne: 10/10/80) mixtures, the microporous Ni2(dobdc) exhibits the longest breakthrough time periods of 240 and 36.4 min g−1, respectively. In the (H2/D2: 50/50) mixture, mesoporous Ni2(olz) exhibits the longest breakthrough time of 15.0 min g−1 owing to its more accessible OMSs and diffusion rate of hydrogen isotope being inclined to adsorb heavier D2 rather than H2. Hence, mesoporous MOFs with abundant OMSs may be ideal candidates for D2/H2 separation.