Many CO2 sorbents have performance degradation issues in humid environment. The recently developed moisture swing sorbent, initially used for CO2 capture from ambient air, faces the same problem of high moisture sensitivity in the adsorption environment with very dilute CO2 concentration (i.e., air). However, the performance of the sorbent, especially its moisture sensitivity, at relative high concentrations of CO2, is still unknown. In this work, the adsorption performance of a resin-based ion-exchange membrane loaded with CO32− (a typical moisture swing sorbent) was investigated in a series of isothermal equilibrium experiments at varying CO2 concentrations and relative humidity. The results showed that the moisture sensitivity of the adsorption capacity of the ion-exchange membrane decreased with the initial CO2 concentration, especially when the initial CO2 concentration was above 4%. The competition mechanism of H2O and CO2 molecules in the membrane material was analyzed by the modified dynamic adsorption model. The present work indicates that the resin-based ion-exchange membrane could be used for carbon dioxide removal in a lot humid environments with relatively high CO2 concentration, such as fruit and vegetable storage room, raw natural gas, and flue gas.
Bibliographical noteThis work was supported by the National Natural Science Foundation of China (11872302 and 12002271) and the Young Talent Support Program of Xi'an Science and Technology Association (095920221368).
- CO2 adsorption
- humid environment
- ion-exchange membrane
- moisture swing sorbent