Abby L. Harvey
GHG Monitor
4/17/2015
A type of smectite clay called lithium-fluorohectorite has been discovered to have impressive carbon capture capabilities, according to research performed at the Norwegian University of Science and Technology and noted in a university news article last week. “Our experiments show that this kind of smectite can capture and retain as much CO2 as other materials that have been studied for this purpose,” Jon Otto Fossum, professor at the Department of Physics, said in the article. The research was published last month as a scientific report in the journal Nature and found that “the smectite Li-fluorohectorite is able to retain CO2 up to a temperature of 35C at ambient pressure, and that the captured CO2 can be released by heating above this temperature,” according to the report.
The report explains that the clay presents several specific characteristics that a carbon capture material should possess, including: “a large effective surface area with good adsorption capacity, selectivity for CO2, regeneration capacity with minimum energy input, allowing reutilization of the material for CO2 adsorption, and low cost and high environmental friendliness.” According the report, “smectite clays are layered nanoporous materials that may be good candidates in this context.”
Further, the researchers discovered that the CO2 capture can be controlled by changing temperatures. “It has previously been concluded that the interlayer CO2 may cause an irreversible adsorption in clay, i.e. even if a clay sample is not exposed to the CO2 gas, CO2 molecules remain in the interlayer space. This means that once intercalated with CO2 the clay mineral will retain these molecules. However, a temperature change can affect the CO2 retention and this makes the process of intercalation and release truly reversible. We found that at a certain threshold temperature, the intensity decreases until the contribution to the scattered intensity from the clay mineral with intercalated CO2 is negligible,” according to the report.
