Channel CO2 in feldspathoids: a review of existing data and new perspectives

The study of volatile constituents in minerals has potential applications ranging from environmental studies to ore research to volcanic hazards. In this paperwe present new data on the volatile (particularly CO(2)) content of a series of feldspathoids belonging to the cancrinite-sodalite group of minerals, in combination with other data collected over the last few years. The work has been essentially done using FTIR microspectroscopy to detect and characterize the speciation of H and C in the micropores of these minerals. We show that most cancrinite-sodalite group of minerals are able to trap CO(2) in their structure in addition to other molecular and anionic species such as H(2)O, OH, F, Cl, SO(4), SO(3) etc. A combination of in situ and annealing heat-treatments shows that the different species in the cancrinite-sodalite group release CO(2) at different temperatures, due to the different connectivity of their pores. Detailed FTIR microspectrometry mappings typically show non-homogeneous distributions of hydrogen and carbon across the samples, and suggest a possible use of these minerals as a tool for geothermometric modelling. The finding that most cancrinite-sodalite group minerals are able to trap carbon dioxide opens a new frontier in the design of materials having potential for carbon sequestration from the atmosphere.