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Atmospheric New Particle Formation from Gas Phase Reactions of Alkanolamines with Sulfuric Acid
SANDRA FOMETE, Jack Johnson, Nanna Myllys, Coty Jen, Carnegie Mellon University
Abstract Number: 359
Working Group: Aerosols, Clouds and Climate
Abstract
Chemical absorption using aqueous alkanolamine solutions such as monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA) is widely used for CO2 capture in several industrial processes. As such, these alkanolamines are likely to be released in large amounts into the atmosphere due to large-scale adoption of this process as countries work towards achieving net-zero carbon emission targets. In addition, these amines are also used in a wide variety of industrial and personal care products. Despite the extensive use of these chemicals, their fate in the atmosphere has not been extensively studied. One likely reaction pathway for these chemicals in the atmosphere is nucleation with sulfuric acid. Computational chemistry suggests that MEA plays a vital role in enhancing sulfuric acid nucleation. However, nucleation kinetics of MEA, as well as that of DEA and TEA with sulfuric, has not been experimentally measured. In this study, we examined nucleation reactions of MEA, DEA, and TEA with sulfuric acid in a flow reactor. These nucleation reactions were carried out in a clean laminar flow reactor operated at ~298-300K. The chemical composition of the freshly nucleated clusters in the flow reactor was analyzed using a custom-built high resolution, atmospheric pressure interface time of flight chemical ionization mass spectrometer (API-ToFCIMS). In addition, the Atmospheric Cluster Dynamics Code (ACDC) is also used to investigate how the formation rates of sulfuric acid-MEA/DEA/TEA compare with experimental measurements. Results indicate that MEA, DEA, and TEA at the parts per trillion (ppt) level can enhance sulfuric acid nucleation in the atmosphere. Though the enhancing potential of these alkanolamines is less than that of dimethylamine (DMA), one of the strongest enhancing agents, it will likely play a key role in new particle formation in the atmosphere as these compounds are increasingly used for the removal of CO2 in the atmosphere. Results from this study improve the current understanding of how new particles form in the atmosphere and will help in evaluating the environmental impact of alkanolamines used for CO2 capture.