ACTIVE CONTROL OF INDOOR CARBON DIOXIDE CONCENTRATION USING ADSORPTIVE CHARACTERISTICS OF ZEOLITES

초록

Ventilation is one of the easiest ways to control the carbon dioxide (CO2) concentration of indoor spaces. However, ventilation is not easy when the outdoor air is seriously polluted, e.g., subway, roadside. In this study, more active way to control indoor CO2 using adsorptive characteristics of zeolite was suggested. Conventional zeolites as 13X and 5A were used as the adsorbent of CO2. A 100 mL of small reactor was prepared, and the nitrogen gas containing 5,000 ppm of CO2 was passed through this reactor at a flow rate of 3 L per minute. CO2 concentration before and after the reactor were monitored by using an infrared CO2 detector. It was observed that 5A adsorbed larger amount of CO2 than 13X. 5A could be reused more than three times by baking at 180 for 24 hours, meanwhile 13X was almost deactivated after just one use. Effects of temperature and pressure on CO2 adsorption and desorption characteristics were also nvestigated. It was observed that the adsorbed CO2 was desorbed better at higher temperature and lower pressure. It was found that conventional zeolite can be used as CO2 adsorbent of indoor spaces.