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Sci Tech
Low-cost capture of CO2
Carbon dioxide (CO2) emanates from the smokestacks of coal-fired power plants and other generators and is a greenhouse gas. Existing CO2 capture techniques involve the use of solid materials that lack sufficient stability for repeated use — or liquid adsorbents that are expensive and require significant amounts of energy.
Researchers have now developed a new, low-cost material for capturing CO2.
Heat management
Combined with improved heat management techniques, the new material could provide a cost-effective way to capture large quantities of carbon dioxide from coal-burning facilities.
Details of the new material, known as hyperbranched aluminosilica (HAS), appeared in the March 19th issue of the Journal of the American Chemical Society. Production of the HAS material is relatively simple, and requires only the mixing of the silica substrate with a precursor of the amine polymer in solution.
The amine polymer is initiated on the silica surface, producing a solid material that can be filtered out and dried. “This is something that you could imagine scaling up for commercial use,” said Christopher Jones, a professor at the Georgia Institute of Technology, where the material was developed.
“Our material has the combination of high capacity, easy synthesis, low cost and a robust ability to be recycled — all the key criteria for an adsorbent that would be used on an industrial scale.”
Testing effectiveness
To test the effectiveness of their new material, the Georgia Tech researchers passed simulated flue gases through tubes containing a mixture of sand and HAS. The CO2 was adsorbed at temperatures ranging from 50 to 75 degrees Celsius, according to a Georgia Institute of Technology press release.
Then the HAS was heated to between 100 and 120 degrees Celsius to drive off the gas so the adsorbent could be used again. The researchers tested the material across 12 cycles of adsorption and desorption, and did not measure a significant loss of capacity.
The HAS material can adsorb up to 5 times as much carbon dioxide as some of the best existing reusable materials. The HAS material works in the presence of moisture, an unavoidable by-product of the combustion process. — Our Bureau
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