Minimizing the effect of oxygen on supported polyamine for direct air capture

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Geoeng Info

Jun 30, 2022, 7:01:05 AMJun 30

Minimizing the effect of oxygen on supported polyamine for direct air capture

Yihe Miao, Yaozu Wang, Xuancan Zhu, Wei Chen, Zhijun He, Lijun Yu, Jia Li


Direct air capture (DAC), as a typical technology of negative emission technologies, is indispensable to neutralizing mobile carbon emissions. The polyamine-loaded adsorbent with high CO2 capacities at extremely low CO2 concentration while maintaining mild regeneration conditions is a promising choice for actual DAC systems. This work comprehensively investigated the effect of oxygen in the air on the selectivity of polyamine-functionalized adsorbents towards CO2 in the adsorption process and the oxidative stability in the desorption process. Results indicate high selectivity toward CO2 and oxidative resistance of adsorbents can be realized by accurately controlling the operating temperature. The oxidation of supported polyamine follows a three-phase mechanism. The oxidative stability of adsorbents varied at oxidation phases distinguished by different operating temperatures. Instructed by that three-phase oxidation mechanism, the optimal regeneration temperature of 80 °C was suggested for supported PEI and TEPA adsorbents. This optimal regeneration temperature can achieve favorable CO2 capture performance and maintain superior oxidative stability. Based on these findings, an air-assisted temperature swing adsorption DAC system was proposed to collect CO2 from the air for agricultural greenhouse.

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