Synthesis of a novel hybrid adsorbent which combines activated carbon and zeolite NaUSY for CO₂ capture by Electric Swing Adsorption (ESA)

Electrical Swing Adsorption is a version of temperature swing adsorption in which the adsorbent is regenerated by Joule heating. To accomplish this feature, the adsorbent must be a continuous, electrically conducting member, which usually restricts the application to activated carbon samples. Unfortunately, the CO₂ adsorption capacity and selectivity of activated carbon is not as good as silica-alumina materials such as zeolites. In addition, the low resistance of activated carbon samples often means that the dominant heat generation occurs at the contact resistance between the electrodes and the sample, depriving the bulk sample of temperature increase. Use of the silica-alumina materials though, is prevented by its electrically insulating properties. In the current work, we present a novel approach to solve this dilemma. We have synthesized a novel hybrid activated carbon (from phenolic resin) and zeolite NaUSY monolith with attractive electrical and adsorption properties. The adsorption capacity of CO₂ on the novel adsorbent was more than twice that of an AC-only material prepared from phenolic resin. The electrical resistance increased from 4.59 × 10⁻⁴ Ω m for activated carbon to 1.18 × 10⁻² Ω m for the hybrid adsorbent so that energy loss in the contacting surfaces between the adsorbent surface and copper electrode was reduced significantly from 73% of the total resistance to 18%. This novel hybrid adsorbent has excellent potential in ESA applications.