Applications of Joule heating in amine-activated carbon fibers for efficient desorption in direct air CO2 capture
Embargo Date
2028-05-27
OA Version
Citation
Abstract
Developing rapid and more efficient mechanisms for sorbent regeneration is imperative in the continued optimization of direct air capture. Porous sorbents coated with polymeric thin films are already capable of rapid absorption of CO2 with a moderate capacity. However, the current mechanism of sorbent regeneration requires external heating of the sorbent, which is both slow and generally inefficient. Here, the work focuses on the use of spermine-activated carbon fibers, a novel CO2 sorbent, as their own heating element via the Joule heating effect. Porous carbon fibers are obtained from combined polymer phase inversion and separation in a wetspinning process, utilizing the process of nonsolvent induced phase separation. Considering the physical properties of these carbon fibers, the polymer concentration and the ratio of the two components in the polymer mixture (polyacrylonitrile and polyvinylpyrrolidone) were found to have significant tuning ability of the inner pore architecture and general mechanical strength of the fibers. The optimized fiber balances pore accessibility, pore surface area (the primary correlate to CO2 absorption capacity), and mechanical strength via these two tuning mechanisms. Electrothermally, the Joule heating effect in this material leads to consistent, rapid, and uniform heating when in ambient air, rapidly achieving a steady-state. A multifiber system has similar rapid heating initially, but can only reach a pseudosteady-state, continuing to heat at a much slower rate as current is run. This can be optimized in a variety of ways, some of which are tested and some of which are proposed in this work. When used in a dynamic gas sorption system, the multifiber system is capable of CO2 desorption and thus rapid sorbent regeneration when the Joule heating effect is induced. This approach represents a novel use of Joule heating for a direct air capture related system and eliminates many of the system constraints that come from the current method, by using the CO2 sorbent, itself, as its own heating element.
Description
2026
License
Attribution-NonCommercial-NoDerivatives 4.0 International