Inverse Adsorption Separation of CO₂/C₂H₂ Mixture in Cyclodextrin-Based Metal–Organic Frameworks

Abstract

The demand for CO 2 /C 2 H 2 separation, especially the removal of CO 2 impurity, continues to grow because of the high-purity C 2 H 2 required for various industrial applications. The adsorption separation of C 2 H 2 and CO 2 via porous materials is gaining a considerable attention as it is more energy-efficient compared with cryogenic distillation. The ideal porous materials are those that preferentially adsorb CO 2 over C 2 H 2 ; however, very few adsorbents meet such requirement. Herein, two isostructural cyclodextrin-based CD-MOFs (CD-MOF-1 and CD-MOF-2) were demonstrated to have an inverse ability to selectively capture CO 2 from C 2 H 2 by single-component adsorption isotherms and dynamic breakthrough experiments. These two MOFs showed excellent adsorption capacity and benchmark selectivity (118.7) for CO 2 /C 2 H 2 mixture at room temperature, enabling the pure C 2 H 2 to be obtained in only one step. This work revealed that these materials were promising adsorbents for obtaining high-purity C 2 H 2 via selectively capturing CO 2 from C 2 H 2 .

RETRACTED ARTICLE: A porous Co(II)–MOF for selective C2H2/CO2 separation and treatment activity on virus-induced COPD via reducing tlr3 gene expression

“…In these cases, the open metal and basic positions are considered to be the origin for the behavior of selective adsorption. Former studies on the porous materials have shown that functional positions and appropriate pore dimension can improve the separation property [15][16][17][18][19]. In comparison with the open metal positions, the basic positions such as nitrogen-donor and oxygen-donor sites are less discussed for the separation of C 2 H 2 / CO 2 .…”

Selective capture of carbon dioxide from hydrocarbons using a metal-organic framework

“…In literature reports to date, the capture of CO 2 over C2 hydrocarbons has so far largely been restricted to cryogenic temperatures and/or static conditions [52][53][54][55]57,61 . With respect to CO 2 /C 2 H 2 mixtures at ambient temperatures, we are aware of only a few reported materials, CD-MOF-1 51 , CD-MOF-2 51 58 for which this inverse trapping of CO 2 has been verified by experimental breakthrough measurements. Since these MOFs adsorb C 2 H 2 (in addition to CO 2 ) strongly at moderate pressures, their uptake ratios are modest.…”

A Universal Porous Adsorbent for the Selective Capture of Carbon Dioxide

“…While only a few nanoporous materials have been reported for the stripping of CO2 from H2/CO2 feedstocks, [45][46] as required for the purification of syngas, this has been identified as a high priority. [47][48] In this light, we conducted breakthrough studies for a 15/85 mixture of CO2/H2 at 293 K and 1.1 bar to show that MUF-16 is able to efficiently separate CO2 from H2. CO2 was retained on the MUF-16 bed while the H2 11 component eluted immediately in a high purity stream, as expected on the basis of the low uptake capacity for this gas (Figure 6d).…”