Characterizing and modeling the mechanical behavior of an anion exchange membrane for carbon capture applications

TL;DR

This paper investigates the mechanical properties of an anion exchange membrane used in moisture swing direct air capture, developing a model to predict its behavior under different environmental conditions.

Contribution

It provides the first comprehensive mechanical characterization and modeling of FAA-3 membrane for improved DAC system design and durability.

Findings

FAA-3 membrane exhibits nonlinear viscous behavior.

Mechanical model accurately predicts membrane response.

Membrane properties vary with temperature and humidity.

Abstract

A new direct air capture (DAC) technology uses a moisture swing (MS) process with anion exchange membranes, potentially offering a more energy-efficient way to remove CO2 from the air. In this MS process, the membrane absorbs CO2 as it dries and releases it when water is added. Understanding the mechanical behavior of these membranes is essential for improving the design and efficiency of DAC systems and prolonging sorbent lifetime. This study tested one anion exchange membrane, Fumasep FAA-3, under mechanical loading and various temperature and humidity conditions to measure its swelling, stiffness, strength, plastic deformation, and stress relaxation. Experimental results were used to identify a mechanical model for FAA-3 that can be used to predict the material's nonlinear viscous behavior under various loads and environments.