Natural clays for CO2 sequestration: study in the form of powder as previous stage before their use in structured filters.

Resumen

The potential application of some natural spanish clays in the retention of CO2 was investigated. Temperature-Programmed Desorption experiments monitored by both thermogravimetry and mass spectrometry, combined with infrared spectroscopy, after treatments with CO2 at r.t. under dynamic conditions were used to evaluate its interaction with the clays. This study was performed not only over the raw materials but also after cationic exchange with NaCl followed by intercalation of a polyalcohol dendrimer. Additionally, textural, structural and compositional characterization of the clays by means of N2 physisorption, X-ray diffraction, SEM-EDS and granulometry was carried out. The results indicate that although the raw clays exhibit some intrinsic capacity to capture CO2, this can be increased by further intercalation of the polyalcohol. Moreover, the strength of the CO2 interaction and therefore the possibility of regeneration of the clays upon saturation can be modulated by their nature and the amount of dendrimer employed. Finally, after screening the powdered clays, those showing the best performance were selected to manufacture clay-based honeycomb monoliths, an advantaged design for applications which require treating high flows of polluted effluents. For this, both extrusion of clay doughs and deposition over a preformed clay-based honeycomb support by washcoating methods were considered.