X-ray Studies of Capture, Storage and Release of CO2
We show experimentally that CO2 intercalates into the interlayer space
of the synthetic smectite clay Li-fluorohectorite (LiFh). The intercalation
occurs for a range of conditions in terms of pressure (5 bar to 20 bar) and
temperature (-20'C to 5'C). The mean basal spacing of the clay layers
in LiFh intercalated by CO2 is found to be approximately 12.0 Å.
We observe that the dynamics depends on the pressure, with a higher
intercalation rate at increased pressure. Even under pressure of 20 bar,
intercalation of CO2 is slower than H2O intercalation in fluorohectorites
by orders of magnitude.
In situ observations show that LiFh is able to retain CO2 in the interlayer
space at room temperature, and the CO2 only starts leaving the clay at
temperatures exceeding 30'C. Hydrated and CO2-intercalated clays are
indistinguishable by use of X-ray diffraction alone. The difference in behavior
at higher temperatures is used as an additional confirmation that
intercalation of residual water is not the cause of the observed swelling.
Furthermore, we report a new intercalation state corresponding to intercalation
of more than one layer of CO2 into the interlamellar space, and
have also observed changes in the intercalation state of a monohydrated
LiFh sample under exposure to CO2.
We believe that the findings, concerning both intercalation and deintercalation,
could be relevant for application of clays related to capture, transport
or storage of CO2.
Place, publisher, year, edition, pages
Institutt for fysikk , 2012. , 145 p.
ntnudaim:7965, MTFYMA fysikk og matematikk, Teknisk fysikk
IdentifiersURN: urn:nbn:no:ntnu:diva-18889Local ID: ntnudaim:7965OAI: oai:DiVA.org:ntnu-18889DiVA: diva2:566350
Fossum, Jon Otto, Professor