Benchmarking selective capture of trace CO<sub>2</sub> from C<sub>2</sub>H<sub>2</sub> using an amine-functionalized adsorbent.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40090945.
- Also identified by DOI 10.1038/s41467-025-57972-7 and PMC identifier 11911411.
- Licence recorded as CC BY-NC-ND.
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Abstract
Purifying C<sub>2</sub>H<sub>2</sub> by removing trace CO<sub>2</sub> is critically needed yet challenged by their analogous physical properties. Herein, we report a commercial resin adsorbent HP20 (Diaion® HP-20 Resin) loaded with polyethyleneimine (PEI@HP20) which selectively captures trace CO<sub>2</sub> and excludes C<sub>2</sub>H<sub>2</sub>. PEI@HP20 possesses a high CO<sub>2</sub> adsorption capacity (4.35 mmol/g) at 100 kPa and 298 K and a record CO<sub>2</sub>/C<sub>2</sub>H<sub>2</sub> uptake ratio compared with all reported CO<sub>2</sub>-selective adsorbents. The ideal adsorbed solution theory selectivity reaches 1.33×10<sup>7</sup>. The pilot-scale pressure-temperature swing adsorption on 2 kg PEI@HP20 further validated that it can obtain >99.99% purity C<sub>2</sub>H<sub>2</sub> from CO<sub>2</sub>/C<sub>2</sub>H<sub>2</sub>(1/99, v/v) mixtures with a high yield of 344.7 g per cycle. The combination of multinuclear solid-state Nuclear Magnetic Resonance, Fourier Transform infrared spectroscopy and density functional theory calculations reveal that the performance of PEI@HP20 relies on a dual chemisorption/physisorption mechanism. This work highlights a promising method to develop green, low cost, high efficiency, and readily scalable CO<sub>2</sub>-selective adsorbent.