Evaluation of moisture effect on low-level CO₂ adsorption by ion-exchanged zeolite

Abstract

To enhance the capture of low-level indoor CO₂, a commercial zeolite (13X) was modified with alkali and alkaline earth metals using an ion-exchange method. Although the calcium-impregnated sorbent (zeo-Ca) showed the largest adsorption capacity, with a strong binding force for carbon dioxide, its regeneration by heat treatment was very difficult. Moisture in the gas flow caused significant decreases in CO₂ adsorption capability as well as in the lifetime of the adsorbents. As for the regeneration gas, the test showed that nitrogen would hinder the CO₂ adsorption more significantly than helium gas. Water vapour and nitrogen gas molecules are apt to competitively occupy the available sites of the adsorbent over the CO₂ molecules.

Keywords:

• carbon dioxide
• adsorption
• temperature programmed desorption
• zeolite
• ion-exchange

Acknowledgements

This work is the outcome of a Manpower Development Program for Energy & Resources, supported by the Ministry of Knowledge and Economy (MKE), Republic of Korea.