A novel solution method for interpreting binary adsorption isotherms from concentration pulse chromatography data

Adsorption separation of carbon dioxide from nitrogen (N-2, which represents air) was investigated by using H-ZSM-5 as the adsorbent with SiO2/Al2O3 ratios of 30 and 280. Pure and binary isotherms at 40 degreesC have been determined experimentally using concentration pulse chromatography. Presently available methods for determining binary isotherms from concentration pulse chromatography data have been reviewed and shown incapable of interpreting this particular binary system. A novel solution method is presented and shown to be superior to the other methods. The binary isotherms for the CO2-N-2 system show an increase in CO2 selectivity with increase in surface heterogeneity. The optimal separation factor for H-ZSM-5-30 was found to be 215 at 0.7% CO2 in the feed, whereas, H-ZSM-5-280 has an optimal separation factor of 48 at 2.7% CO2 in the feed.