Direct air capture (DAC) can provide an impactful, engineered approach to combat climate change by removing carbon dioxide (CO₂) from the air. However, to meet climate goals, DAC needs to be scaled at a rapid rate. Current DAC approaches use engineered contactors filled with chemicals to repeatedly capture CO₂ from the air and release high purity CO₂ that can be stored or otherwise used. This review article focuses on two distinctive, commercial DAC processes to bind with CO₂: solid sorbents and liquid solvents. We discuss the properties of solvents and sorbents, including mass transfer, heat transfer and chemical kinetics, as well as how these properties influence the design and cost of the DAC process. Further, we provide a novel overview of the considerations for deploying these DAC technologies, including concepts for learning-by-doing that may drive down costs and material requirements for scaling up DAC technologies.

直接空气捕获 (DAC) 可以通过从空气中去除二氧化碳 (CO ₂ )来提供一种有效的工程方法来应对气候变化。然而，为了实现气候目标，DAC 需要快速扩展。当前的 DAC 方法使用填充有化学品的工程接触器来重复从空气中捕获 CO ₂并释放可储存或以其他方式使用的高纯度 CO ₂。这篇评论文章重点介绍了两种与 CO ₂结合的独特商业 DAC 工艺：固体吸附剂和液体溶剂。我们讨论了溶剂和吸附剂的特性，包括传质、传热和化学动力学，以及这些特性如何影响 DAC 工艺的设计和成本。此外，我们对部署这些 DAC 技术的考虑因素进行了新颖的概述，包括边做边学的概念，这些概念可能会降低成本和扩大 DAC 技术的材料要求。