http://www.reportingclimatescience.com/news-stories/article/clay-can-be-used-for-carbon-capture.html
by Steinar Brandslet , Norwegian University of Science and Technology Carbon capture will play a central role in helping the nations of the world manage and reduce their greenhouse gas emissions. Many materials are being tested for the purpose of capturing CO2. New results show that ordinary clay can work just as effectively as more advanced materials. “It is quite remarkable that clay can capture as much CO2 as other materials that are being investigated,” says Jon Otto Fossum, professor at the Department of Physics at the Norwegian University of Science and Technology (NTNU). Clay offers many benefits compared to other materials, particularly because other potential materials can be expensive, difficult to produce, toxic and not particularly environmentally friendly. A possible practical future use of this discovery could be to include clays in CO2 filters for industrial-scale CO2 emissions reduction. “What we are doing is basic research,” Fossum says. “It will take more research to develop the technology, so we don’t expect clay-based CO2 capture to be readily available anytime soon.” NTNU researchers Leander Michels, a PhD candidate and Fossum led the research effort, in cooperation with researchers from the Institute for Energy Technology in Kjeller, Norway, and scientists from the Slovak University of Technology, the MaxIVLab at Lund University and the Universidade de Brasilia. The results were recently published in Scientific Reports, a peer-reviewed journal published by the Nature Publishing Group. A good material for capturing CO2 must meet specific requirements. It should have a large surface area and good adsorbtion capability. It should be able to capture CO2 selectively before it captures other molecules, it should not need a lot of energy for it to work, and it must be reusable. Moreover, it must be inexpensive and environmentally friendly. Certain clay minerals meet these criteria, particularly smectite, a group of clay minerals that swell in contact with water, which are known as layered nanosilicates. The researchers used synthetic smectite in their experiments. Artificial clays can actually be inexpensive to make. The researchers found that CO2 in gaseous form binds to smectite, and that it is not only the smectite clay surfaces in themselves that are responsible for binding CO2, but principally that ions associated with the clay surfaces are the active capturers. A smectite clay called lithium-fluorohectorite can retain CO2 at temperatures up to 35 degrees C at ambient pressure. The CO2 that is captured by the clay is released when it is heated to temperatures above this limit, which allows CO2 capture to be controlled. “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,” Fossum says. http://www.nature.com/srep/2015/150305/srep08775/full/srep08775.html Abstract A good material for CO2 capture should possess some specific properties: (i) a large effective surface area with good adsorption capacity, (ii) selectivity for CO2, (iii) regeneration capacity with minimum energy input, allowing reutilization of the material for CO2 adsorption, and (iv) low cost and high environmental friendliness. Smectite clays are layered nanoporous materials that may be good candidates in this context. Here we report experiments which show that gaseous CO2 intercalates into the interlayer nano-space of smectite clay (synthetic fluorohectorite) at conditions close to ambient. 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. Intercalation and Retention of Carbon Dioxide in a Smectite Clay promoted by Interlayer Cations by L. Michels, J. O. Fossum, Z. Rozynek, H. Hemmen, K. Rustenberg, P. A. Sobas, G. N. Kalantzopoulos, K. D. Knudsen, M. Janek, T. S. Plivelic and G. J. da Silva published in Scientific Reports 5, Article number: 8775 doi:10.1038/srep08775 -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
