Connecting Material Characteristics with System Properties for Membrane-Based Direct Air Capture (m-DAC) Using...

This paper presents a process modeling approach for a two-staged membrane-based direct air capture (m-DAC) process, considering material characteristics, membrane separation, and system properties. m-DAC is a negative emissions technology for capturing dilute CO₂ from air. Its continuous and modular nature could reduce economic challenges compared to sorption-based processes, which require costly regeneration. Facilitated transport membranes, with specialized CO₂ carriers, offer higher performance than traditional sorption-diffusion membranes. Their key properties-the CO₂ apparent diffusion coefficient () and equilibrium constant (K _eq)-determine membrane separation properties such as CO₂ permeance and CO₂/N₂ selectivity. This work maps these inputs to feasible output spaces such as for CO₂ recovery, purity, and capture cost. Additionally, inverse design is used to determine the required membrane properties for target system outcomes. Overall, this study provides a framework for membrane researchers to design cost-effective, scalable m-DAC solutions.