Grossmann Quirin, Saenz-Cavazos Paola A, Ferru Nicole, Williams Daryl R, Mazzotti Marco
Institute of Energy and Process Engineering, ETH Zurich, Sonneggstrasse 3, 8092 Zurich, Switzerland.
Department of Chemical Engineering, Imperial College London, London SW7 2AZ, U.K.
Ind Eng Chem Res. 2025 Mar 19;64(13):7165-7175. doi: 10.1021/acs.iecr.4c04581. eCollection 2025 Apr 2.
Water vapor is an unavoidable component of ambient air that sorbents designed for atmospheric CO capture must contend with. Amine functionalized sorbents often exhibit an enhancement of CO uptake in the presence of moisture through a variety of mechanisms, and in this work, we investigate the coadsorption of water and CO on amine functionalized alumina. Sorbent performance is examined under varying levels of humidity and temperature using three common measurement techniques: gravimetric, volumetric, and breakthrough methods. Our findings show that water increasingly enhances CO adsorption up to the monolayer saturation point of water, above which no further enhancement is observed. Competitive adsorption is observed primarily at low relative humidities, and a novel dual-site isotherm model is developed that successfully describes these behaviors. Additionally, this study highlights the unique advantages of each measurement technique for accurately characterizing sorbent performance under direct air capture (DAC) conditions. These insights contribute to the understanding and optimization of amine-based sorbents in DAC applications.
水蒸气是环境空气中不可避免的成分，用于大气中二氧化碳捕集的吸附剂必须应对这一情况。胺功能化吸附剂在有水分存在时，常常通过多种机制表现出对二氧化碳吸附量的增加。在这项工作中，我们研究了水和二氧化碳在胺功能化氧化铝上的共吸附。使用三种常见的测量技术：重量法、容量法和突破法，在不同湿度和温度水平下考察吸附剂性能。我们的研究结果表明，在水的单层饱和点之前，水对二氧化碳吸附的增强作用不断增加，超过该点则未观察到进一步增强。主要在低相对湿度下观察到竞争吸附现象，并开发了一种新型双位点等温线模型，该模型成功地描述了这些行为。此外，本研究突出了每种测量技术在直接空气捕集（DAC）条件下准确表征吸附剂性能方面的独特优势。这些见解有助于理解和优化DAC应用中基于胺的吸附剂。
