Collaborative Research: Investigation of Mass and Energy Transfer Mechanisms in Stimuli-Responsive Smart Sorbents for Direct Air Capture

合作研究：用于直接空气捕获的刺激响应智能吸附剂的质量和能量传递机制的研究

• 批准号: 2230593
• 负责人: Muhammad Sahimi
• 金额: $ 30万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2230593&HistoricalAwards=false
• 关键词: Collaborative; Research; Investigation; Mass; Energy

Mitigating and removing greenhouse gas emissions such as carbon dioxide (CO2) from the atmosphere is one of today's most pressing grand challenges. One possible approach to address this challenge is through direct air capture technologies (DAC). DAC technologies can extract CO2 directly from the atmosphere to be stored permanently. Traditional methods for separating gaseous mixtures involve either adsorbing high-pressure gases onto a solid surface and releasing (desorbing) them when the pressure is reduced (known as pressure swing adsorption) or using temperature changes to achieve separation (known as temperature swing adsorption). However, these methods are unsuitable for DAC systems because the concentration gradient, which drives the mass transfer of CO2, is very small. As a result, these methods are highly inefficient in terms of energy usage. Additionally, the current state-of-the-art sorbent materials based on amines or ionic liquids require a lot of energy to desorb the CO2 and regenerate the sorbents. Furthermore, since most sorbent materials have low thermal conductivity, externally heating them for regeneration is inefficient and leads to additional heat losses. It is crucial to develop new materials and technologies that can address these drawbacks and enable the successful implementation of large-scale DAC systems. This project will investigate a class of CO2 sorbent materials that can be induced to release the adsorbed CO2 by applying an external magnetic field. The magnetic field generates local heat within the material, so external energy input is not required. The research will yield new insights into the fundamental energy and mass transfer mechanisms in these magnetic field-responsive sorbents (MF-RSs). The project will also provide opportunities for undergraduate student research experiences, curriculum development, and K-12 STEM outreach at the Missouri University of Science & Technology and the University of Southern California.The purpose of this work is to gain a fundamental understanding of energy and mass transfer mechanisms in MF-RSs for use in DAC systems, namely, composites of F3O4 magnetic nanoparticles and microporous metal-organic frameworks (F3O4/MOF-amine) or mesoporous aminosilicates (Fe3O4/SiO2-amine). The external magnetic field generates local heat due to the static hysteresis and dynamic core losses of the magnetic nanoparticles. The adsorbed CO2 is desorbed without external heating, overcoming the issue of low thermal conductivity of most sorbent materials and avoiding the heat losses accompanying externally heated methods. Computational and experimental investigations will be conducted to understand the factors affecting CO2 release and system regeneration in MF-RSs. The intermolecular attractions that result in the low-energy release of CO2 from magnetic sorbents upon exposure to an external magnetic field will be characterized. Specifically, the research will probe the extent of electron transfer perturbation upon magnetic field induction. The study will also elucidate the effects of heat capacity-magnetization tradeoffs on diffusive thermal and molecular transfers. Finally, the magnetic field-triggered CO2 transport mechanisms during sorbent regeneration in the presence of oxygen, nitrogen, and water will be investigated. A host of experimental and computational techniques will be applied to reveal the energy and mass transfer mechanisms of CO2 adsorption and desorption from MF-RSs in the presence of an external magnetic field. These techniques include molecular-level in-situ spectroscopic measurements and transient desorption tests such as electron paramagnetic resonance (EPR) spectroscopy, frequency-domain thermoreflectance (FDTR), zero-length column (ZLC), and magnetic induction swing adsorption (MISA), which will be combined with density-functional theory (DFT) and nanoscale molecular dynamics simulations. The investigation will open new avenues for developing low-energy sorbent regeneration systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

减轻和去除大气中的温室气体排放（例如二氧化碳（CO2））是当今最紧迫的挑战之一。解决这一挑战的一种可能方法是通过直接空气捕获技术（DAC）。 DAC技术可以直接从大气中提取二氧化碳，以永久存储。分离气态混合物的传统方法涉及在压力降低（称为压力摇摆吸附）或使用温度变化以实现分离时（称为温度摆动吸附）时，将高压气体吸附到固体表面并释放（解吸）。但是，这些方法不适合DAC系统，因为驱动CO2传质的浓度梯度非常小。结果，这些方法在能源使用方面效率很低。此外，基于胺或离子液体的当前最新吸附剂材料需要大量能量来吸收二氧化碳并再生吸附剂。此外，由于大多数吸附剂材料的热导率较低，因此在外部加热以使其再生效率低下，并导致额外的热量损失。开发可以解决这些缺点并成功实施大规模DAC系统的新材料和技术至关重要。该项目将研究一类二氧化碳吸附剂材料，这些材料可通过施加外部磁场来释放吸附的二氧化碳。磁场会在材料中产生局部热量，因此不需要外部能量输入。这项研究将为这些磁场响应吸附剂（MF-RSS）中的基本能量和传质机制提供新的见解。该项目还将在密苏里科学技术大学和南加州大学的本科生研究经验，课程发展和K-12 STEM外展提供机会（F3O4/MOF-amine）或介孔氨基硅（Fe3O4/Sio2-胺）。由于磁性纳米颗粒的静态滞后和动态核心损失，外部磁场会产生局部热量。吸附的二氧化碳是在没有外部加热的情况下解吸的，克服了大多数吸附剂材料的导热率低的问题，并避免了伴随外部加热方法的热量损失。将进行计算和实验研究，以了解影响MF-RS中CO2释放和系统再生的因素。将表征导致磁场从磁性吸附剂中释放到外部磁场后低能释放的分子间景点。具体而言，该研究将探测磁场诱导时电子转移扰动的程度。这项研究还将阐明热容量 - 磁性折衷方案对扩散热和分子转移的影响。最后，将研究磁场触发的二氧化碳转运机制，在氧气，氮和水存在下的吸附剂再生过程中。将应用大量的实验和计算技术来揭示在存在外部磁场的情况下二氧化碳吸附的能量和传质机制和从MF-RS中解吸的能量和传质机制。 These techniques include molecular-level in-situ spectroscopic measurements and transient desorption tests such as electron paramagnetic resonance (EPR) spectroscopy, frequency-domain thermoreflectance (FDTR), zero-length column (ZLC), and magnetic induction swing adsorption (MISA), which will be combined with density-functional theory (DFT) and nanoscale molecular dynamics模拟。该调查将为开发低能吸附剂再生系统开放新的途径。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准，被认为值得通过评估来提供支持。