Adsorption and Desorption Characteristics of Carbon Dioxide at Low Concentration on Zeolite 5A and 13X

A way to adsorptively remove indoor carbon dioxide at relatively lower concentration under ambient temperature was studied. A small lab-scale carbon dioxide adsorption and desorption reactors were prepared, and 5A and 13X zeolites were packed in this reactors to investigate their adsorption and desorption characteristics. The inflow carbon dioxide concentration was controlled to 5,000 ppm, relatively higher concentration found in indoor spaces with air quality problems, by diluting carbon dioxide with nitrogen gas. The flow rate was varied as 1 similar to 5 L/min, and the carbon dioxide concentration after this reactor was constantly monitored to examine the adsorption characteristics. It was found that 5A adsorbed more carbon dioxide than 13X. A lab-scale carbon dioxide desorption reactor was also prepared to investigate the desorption characteristics of zeolites, which is essential for the regeneration of used zeolites. The desorption temperature was varied as 25 similar to 200 degrees C, and the desorption pressure was varied as 0.1 - 1.0 bar. Carbon dioxide desorbed better at higher temperature, and lower pressure. 5A could be regenerated more than three times by thermal desorption at 180 degrees C. It is required to modify zeolites for higher adsorption and better regeneration performances.