Moderately polarized carborane-MOF with inverse C <sub>2</sub> selectivity for one-step polymer-grade ethylene purification
Ethylene purification from ternary C<sub>2</sub> mixtures (C<sub>2</sub>H<sub>2</sub>/C<sub>2</sub>H<sub>4</sub>/C<sub>2</sub>H<sub>6</sub>) typically requires multi-step processes due to competing adsorption mechanisms in conventional adsorbents. Herein, we report a carborane-based metal-organic framework (CB-Zn-DPG) featuring moderately polarized pore surfaces that inverts traditional selectivity trends. Unlike polar MOFs (C<sub>2</sub>H<sub>2</sub> > C<sub>2</sub>H<sub>4</sub> > C<sub>2</sub>H<sub>6</sub>) or nonpolar MOFs (C<sub>2</sub>H<sub>6</sub> > C<sub>2</sub>H<sub>4</sub> > C<sub>2</sub>H<sub>2</sub>), CB-Zn-DPG simultaneously captures both C<sub>2</sub>H<sub>2</sub> (61.5 cm<sup>3</sup> g<sup>-1</sup>) and C<sub>2</sub>H<sub>6</sub> (44.0 cm<sup>3</sup> g<sup>-1</sup>) preferentially over C<sub>2</sub>H<sub>4</sub> (42.4 cm<sup>3</sup> g<sup>-1</sup>) at 298 K and 1.0 bar, with higher isosteric heats for impurities (C<sub>2</sub>H<sub>2</sub> 31.5 kJ mol<sup>-1</sup>; C<sub>2</sub>H<sub>6</sub> 29.8 kJ mol<sup>-1</sup><i>vs</i>. C<sub>2</sub>H<sub>4</sub> 25.9 kJ mol<sup>-1</sup>). DFT calculations reveal multi-site van der Waals interactions at the channel centers for C<sub>2</sub>H<sub>2</sub>/C<sub>2</sub>H<sub>6</sub>, while C<sub>2</sub>H<sub>4</sub> adsorbs weakly at the pore corners. Dynamic breakthroughs confirm direct production of >99.99% polymer-grade C<sub>2</sub>H<sub>4</sub> from equimolar C<sub>2</sub>H<sub>4</sub>/C<sub>2</sub>H<sub>6</sub> (50/50) and ternary C<sub>2</sub>H<sub>2</sub>/C<sub>2</sub>H<sub>4</sub>/C<sub>2</sub>H<sub>6</sub> (1/90/9) mixtures in a single column operation. This work establishes pore-surface polarity engineering as a paradigm for challenging hydrocarbon separations.
Authors
- Lingyao Wang (ORCID: https://orcid.org/0000-0001-8584-8358)
- Guangzu Xiong
- Changhong Liu (ORCID: https://orcid.org/0000-0001-8386-5939)
- Yuanbin Zhang (ORCID: https://orcid.org/0000-0002-8268-384X)
- Yuzhe Wang (ORCID: https://orcid.org/0000-0003-3474-7957)
- Wenlei Yang
- Yiwen Yuan
- H. Wang (ORCID: https://orcid.org/0009-0001-2467-5331)
Institutions
- Zhejiang Normal University (CN)
- University of Nottingham Ningbo China (CN)
- Ministry of Education (PT)
Publication Details
- Journal
- Materials Horizons
- Published
- 2025-10-04
- DOI
- https://doi.org/10.1039/d5mh01641j
- Citations
- 2
- Primary Topic
- Metal-Organic Frameworks: Synthesis and Applications
- Type
- article
- Field-Weighted Citation Impact
- 1.07