Komma Ramesh B, Dillon Gregory P
School of Engineering, Penn State Erie, The Behrend College, Erie, Pennsylvania 16563, United States.
ACS Omega. 2024 Jul 20;9(30):32881-32892. doi: 10.1021/acsomega.4c03551. eCollection 2024 Jul 30.
Polyethylenimine (PEI) has been shown to be promising for direct air capture (DAC) of carbon dioxide and has potential for commercial scale-up globally. Laboratory scale processes include multiple steps, such as mixing, solvent extraction, vacuum application, sonication, and various flushes and activation steps. It is critical to properly control these operating parameters to achieve higher capture capacity as a result of the optimized material configuration. This study adopts previously published pelletization processes for PEI-infiltrated mesoporous foam silica (mesoporous silica foam) to uncover the adsorption mechanisms and optimize the associated fabrication steps, such as sonication, to achieve higher sorbent productivity. A high capture capacity was achieved at 46 °C for 75 wt % PEI loading (2.27 mmol/g) followed by PEI_MSF 70 (1.81 mmol/g) and PEI_MSF 80 (1.44 mmol/g). As part of the optimization, sonication parameters of frequency, amplitude, and time were modified for PEI_MSF 75 sorbent, which resulted in the highest uptake capacity of 3.04 mmol/g (sonicated at 40 kHz and a wave amplitude of 50% for 30 s). These preliminary results would tend to prove that sonication energy affects carbon capture capacity, although there is still a lack of understanding regarding the exact underlying mechanism, suggesting the need for further investigation. It is important to note that the present work is focused on the adsorption mechanisms and not desorption or durability of the capture performance. Ongoing research addresses these factors. This paper is intended to establish baseline DAC behavior of a promising capture medium and begins probing the optimization spectrum by considering the effects of sonication energy on adsorption. Ongoing work intends to address potential abbreviations of the full range of process steps and furthers the understanding of kinetics by considering the desorption and resorption attributes.
聚乙烯亚胺（PEI）已被证明在二氧化碳直接空气捕获（DAC）方面具有前景，并在全球范围内具有商业扩大规模的潜力。实验室规模的工艺包括多个步骤，如混合、溶剂萃取、抽真空、超声处理以及各种冲洗和活化步骤。由于材料配置得到优化，正确控制这些操作参数对于实现更高的捕获能力至关重要。本研究采用先前发表的用于PEI渗透介孔泡沫二氧化硅（介孔二氧化硅泡沫）的造粒工艺，以揭示吸附机制并优化相关制造步骤，如超声处理，以实现更高的吸附剂生产率。在46°C下，对于75 wt% PEI负载量（2.27 mmol/g）实现了高捕获能力，其次是PEI_MSF 70（1.81 mmol/g）和PEI_MSF 80（1.44 mmol/g）。作为优化的一部分，对PEI_MSF 75吸附剂的超声频率、振幅和时间参数进行了修改，从而实现了最高吸收容量3.04 mmol/g（在40 kHz和50%波幅下超声处理30 s）。这些初步结果倾向于证明超声能量会影响碳捕获能力，尽管对确切的潜在机制仍缺乏了解，这表明需要进一步研究。需要注意的是，目前的工作重点在于吸附机制，而非捕获性能的解吸或耐久性。正在进行的研究涉及这些因素。本文旨在建立一种有前景的捕获介质的基线DAC行为，并通过考虑超声能量对吸附的影响开始探索优化范围。正在进行的工作旨在解决整个工艺步骤的潜在简化问题，并通过考虑解吸和再吸附属性进一步加深对动力学的理解。
