Investigation of irreversible CO2 interactions with clay minerals for the passive regulation of CO2 in indoor environments
Résumé
While the passive moisture buffering properties of earthen materials are well known, recent studies have explored their potential to improve indoor air quality by buffering indoor pollutants, particularly CO2. Previous research has shown that the material interacts with CO2, but that some of the adsorbed CO2 may not be fully released in a humid environment, which is investigated in this study. To investigate the physico-chemical interactions, different clay minerals with different chemical composition and structures were studied. Measurements using thermogravimetry and mass spectrometry were carried out on samples ex-posed to elevated CO2 levels and showed no carbonate formation or other strongly bound CO2, suggesting that the observed irreversibility is not due to pre-cipitation of new phases but rather to CO2 dissolution in water. This suggests that CO2 retention may be fully reversible under certain conditions.