Insights into the Oxidative Degradation Mechanism of Solid Amine Sorbents for CO2 Capture from Air: Roles of Atmospheric Water |
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Authors: | Dr. Juliana S. A. Carneiro Dr. Giada Innocenti Hyun June Moon Yoseph Guta Laura Proaño Prof. Dr. Carsten Sievers Dr. Miles A. Sakwa-Novak Dr. Eric W. Ping Prof. Dr. Christopher W. Jones |
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Affiliation: | 1. School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332 USA;2. Global Thermostat LLC, 10275 E106th Ave, Brighton, CO 80601 USA |
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Abstract: | Direct air capture (DAC) processes for extraction of CO2 from ambient air are unique among chemical processes in that they operate outdoors with minimal feed pretreatments. Here, the impact of humidity on the oxidative degradation of a prototypical solid supported amine sorbent, poly(ethylenimine) (PEI) supported on Al2O3, is explored in detail. By combining CO2 adsorption measurements, oxidative degradation rates, elemental analyses, solid-state NMR and in situ IR spectroscopic analysis in conjunction with 18O labeling of water, a comprehensive picture of sorbent oxidation is achieved under accelerated conditions. We demonstrated that the presence of water vapor can play an important role in accelerating the degradation reactions. From the study we inferred the identity and kinetics of formation of the major oxidative products, and the role(s) of humidity. Our data are consistent with a radical mediated autooxidative degradation mechanism. |
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Keywords: | Amines CO2 Adsorption Direct Air Capture Oxidative Degradation Solid Sorbents |
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