Design of Electrified Fiber Sorbents for Direct Air Capture with Electrically-Driven Temperature Vacuum Swing Adsorption.

Abstract

Joule heating is becoming accepted as a highly efficient regeneration technique for temperature vacuum swing adsorption in direct air capture (DAC). This acknowledgment arises from its ability to rapidly generate and transfer heat, along with the convenience of obtaining electrical power from renewable sources. This study presents a unique electrified fiber sorbent (i.e., e-fiber) design that facilitates Joule heating, enabling energy-efficient electrically-driven temperature-vacuum swing adsorption (e-TVSA) for DAC. The e-fiber sorbent is produced via a dip coating technique, in which a silver composite solution is applied to the surface of an open-porous polymer matrix. The resulting ultra-thin, interconnected porous conductive layer on the fiber surface not only minimizes the increase in diffusion resistance even after the surface coating process but also offers exceptionally low electrical resistance (0.5 Ω cm^-1). The e-fiber sorbent module achieves a desorption temperature of 110 °C in 80 s at 3 V. Notably, only a 5% reduction in capacity is recorded following repeated cycles of e-TVSA at a CO₂ concentration of 400 ppm. The complicated nature of heat transfer processes is clarified caused by Joule heating in the e-fiber sorbent module through detailed case studies conducted with computational simulations, offering insights for design optimization and system engineering.