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X-ray Studies of Carbon Dioxide Intercalation in Na-Fluorohectorite Clay at Near-Ambient Conditions
journal contribution
posted on 2012-01-24, 00:00 authored by Henrik Hemmen, Erlend G. Rolseth, Davi M. Fonseca, Elisabeth L. Hansen, Jon Otto Fossum, Tomás S. PlivelicWe show experimentally that gaseous CO2 intercalates
into the interlayer space of the synthetic smectite clay Na-fluorohectorite
at conditions not too far from ambient. The mean interlayer repetition
distance of the clay when CO2 is intercalated is found
to be 12.5 Å for the conditions −20 °C and 15 bar.
The magnitude of the expansion of the interlayer upon intercalation
is indistinguishable from that observed in the dehydrated–monohydrated
transition for H2O, but the possibility of water intercalation
is ruled out by a careful analysis of the experimental conditions
and repeating the measurements exposing the clay to nitrogen gas.
The dynamics of the process is observed to be dependent on the pressure,
with a higher intercalation rate at increased pressure. The rate of
CO2 intercalation at the studied conditions is found to
be several orders of magnitude slower than the intercalation rate
of water or humidity at ambient pressure and temperature.