(694g) Composite Adsorbents with Anion-Pillared Microporous Materials Embedded in Poly (Ionic Liquids) for Flue Gas Desulfurization

As one of the most notorious air pollutants, sulfur dioxide (SO₂) has been corroding the natural ecology and the human society since the onset of fossil fuel combustion. It is also one of the initiators for the formation of inhalable particle matters that are hazardous to human health. Hence, technologies to reduce the SO₂ emission are under intensive research.

Flue gas is one of the main SO₂ sources. Though fuel desulfurization technologies have been under rapid development, elimination of SO₂ from flue gas is still necessary due to the enormous amount of emission. Traditional processes involving alkaline solution or limestone will produce extra wastes. Adsorption, however, can be waste-free and even provide the possibility of SO₂ recovery. Thus, new materials with impressive adsorption performances are being designed. Since flue gas usually contains only about 0.2%(v/v) of SO₂, the adsorbents are required to grab SO₂ at very low partial pressures. Meanwhile, with around 10%(v/v) CO₂ in the gas mixture, the adsorbents should also possess high SO₂/CO₂ selectivity to avoid frequent regeneration. Metal-organic frameworks (MOFs) have shown sufficiently high SO₂ adsorption capacity. However, these materials also take up CO₂ readily, resulting in limited SO₂/CO₂ selectivity.

Herein, we present a novel composite material consisting of anion-pillared microporous materials and poly (ionic liquids) for flue gas desulfurization. As an attractive class of MOFs, anion-pillared microporous materials exhibited extremely high SO₂ adsorption capacities at low partial pressures, as revealed by our previous work. Poly (ionic liquids), on the other hand, showed distinctively high SO₂/CO₂ selectivity via particular swelling toward SO₂. By embedding anion-pillared materials into poly (ionic liquids), we obtained a new class of composite adsorbents able to grab SO₂ at an extremely low partial pressure while selectively repulse CO₂, which is especially adequate for flue gas desulfurization. The strategy described here can also be applied to other adsorbents for separation performance improvement.

Acknowledgement:

This research was supported by the National Natural Science Foundation of China (No. 21725603), Zhejiang Provincial Natural Science Foundation of China (No. LZ18B060001), and the National Program for support of Top-notch Yong Professionals (H. X.)

References:

1. X. L. Cui, Q. W. Yang, L. F. Yang, R. Krishna, Z. G. Zhang, Z. B. Bao, H. Wu, Q. L. Ren, W. Zhou, B. L. Chen, H. B. Xing. Adv. Mater. 2017, 29, 1606929.

2. L. Xia, Q. Cui, X. Suo, Y. H. Li, X. L. Cui, Q. W. Yang, J. H. Xu, Y. W. Yang and H. B. Xing. Adv. Funct. Mater. 2018, 28, 1704292.