[Image above] Credit: Gareth Simpson; Flickr CC BY 2.0
This time, however, it isn’t a muscular man in a leotard and cape who stands ready to save the day.
According to research from the Norwegian University of Science and Technology (NTNU), it’s clay that stands poised to save the world from environmental evils (a.k.a. greenhouses gases).
The team, led by NTNU’s Leander Michels and Jon Otto Fossum, investigated clay’s carbon capture capabilities and found that your run-of-the-mill clay can get the job done “just as effectively as other materials.”
“It is quite remarkable that clay can capture as much CO2 as other materials that are being investigated,” says Fossum, professor at NTNU’s department of physics, in an NTNU news release.
The findings, published in Scientific Reports, show that certain types of clay, including the synthetic smectite used in the team’s experiments, have surfaces that prove particularly effective in binding CO2. But the surfaces, though super, play more of a supporting role in capturing CO2. Ions in the surfaces are the true heroes and “active capturers.”
The optimal material for capturing CO2 has several requirements, the team says. In addition to having a large surface area with good adsorbtion capability, the material must show selectivity for CO2, regeneration capacity with minimum energy input, and be both low cost and environmentally friendly.
According to the paper’s abstract:
The rate of intercalation, as well as the retention ability of CO2 was found to be strongly dependent on the type of the interlayer cation, which in the present case is Li+, Na+ or Ni2+. Interestingly, we observe that the smectite Li-fluorohectorite is able to retain CO2 up to a temperature of 35°C at ambient pressure, and that the captured CO2 can be released by heating above this temperature. Our estimates indicate that smectite clays, even with the standard cations analyzed here, can capture an amount of CO2 comparable to other materials studied in this context.
Clay is not only cheaper, easier to produce, non-toxic, and more environmentally friendly than other materials used for carbon capture, but could possibly be used in CO2 filters for reducing emissions on the industrial scale, say researchers.
Although the findings are promising, there is still work to be done.
“What we are doing is basic research,” Fossum says in the release. “It will take more research to develop the technology, so we don’t expect clay-based CO2 capture to be readily available anytime soon.”
The research team also included scientists from the Institute for Energy Technology (Norway), Slovak University of Technology (Slovakia), the MaxIVLab at Lund University (Sweden), and the Universidade de Brasilia (Brazil). The paper is “Intercalation and retention of carbon dioxide in a smectite clay promoted by interlayer cations” (DOI: 10.1038/srep08775).