In recent years, marine carbon removal technologies have gained attention as a means of reducing greenhouse gas concentrations. One family of these technologies is electrochemical systems, which employ Faradaic reactions to drive alkalinity-swings and enable dissolved inorganic carbon (DIC) removal as gaseous CO₂ or as solid minerals. In this work, we develop a thermodynamic framework to estimate upper bounds on performance for Faradaic DIC removal systems. To assess the fundamental mass balances of these systems, we first define unit operations in the DIC/total alkalinity (TA) space. By coupling a seawater speciation model to an electrochemical framework, we provide a generalized comparison of gas evolution and mineralization DIC removal routes, focusing on asymmetric charge/discharge systems. We then show how this framework can be extended to other processes, such as those employing dilution schemes. Finally, we provide a minimum energetic assessment of mCDR pathways relative to direct air capture. Overall, this thermodynamic framework aims to guide system and process design and to drive material discovery and engineering for future electrochemical marine DIC removal systems.

中文翻译：

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电化学海洋无机碳去除的热力学


近年来，海洋碳去除技术作为降低温室气体浓度的一种手段而受到关注。这些技术的一个系列是电化学系统，它采用法拉第反应来驱动碱度波动，并能够以气态_CO2 或固体矿物的形式去除溶解的无机碳 （DIC）。在这项工作中，我们开发了一个热力学框架来估计法拉第DIC去除系统的性能上限。为了评估这些系统的基本质量平衡，我们首先在 DIC/总碱度 （TA） 空间中定义单元操作。通过将海水形态模型与电化学框架耦合，我们提供了气体逸出和矿化 DIC 去除路线的通用比较，重点是不对称的充电/放电系统。然后，我们展示了如何将该框架扩展到其他工艺，例如采用稀释方案的工艺。最后，我们提供了相对于直接空气捕获的 mCDR 途径的最低能量评估。总体而言，该热力学框架旨在指导系统和工艺设计，并推动未来电化学船用 DIC 去除系统的材料发现和工程设计。