Collecting carbon in a concrete jungle
Thanks to microscopic tubes that suck in carbon dioxide from the air, land that has been deemed unsuitable for tree planting could still be used to reduce levels of carbon dioxide in the atmosphere - even without trees. A team of innovative researchers from the University of Edinburgh, United Kingdom believe that a one 1m2 unit of land containing these tiny tubes could adsorb the same amount of carbon that 10 average-sized trees can. The researchers hope that in the future, larger versions of the units, developed as part of a project titled NANOTUBES FOR CARBON CAPTURE, could be placed beside motorways to make better use of unused land and help reduce our collective carbon footprint. Some 50% of CO2 emissions come from small, distributed sources and transport. Considerable progress could be made in meeting environmental aspirations if it were possible to develop a small-scale low maintenance device for local combined heat and power (CHP) plants or domestic use. One of the major challenges lies in the development of a material that can efficiently adsorb CO2 as well as being able to de-absorb the CO2 for further storage or use. 'In some ways, the unit would work like an artificial tree,' comments project leader Professor Campbell. 'A key advantage, of course, is that the units could be used in built-up urban areas where tree planting is not possible.' Professor Campbell continues to explain how the tubes would work in practice: 'The tube material will be specially designed at the nanoscale to be highly porous, in order to adsorb as much carbon dioxide as possible ... A key task is to engineer the chemistry of the tubes so that they only adsorb carbon dioxide without taking water vapour, for instance, out of the air as well.' Each individual tube will be around 1 micrometre long and just 1 nanometre in diameter - 1 micrometre is 1 millionth of a metre and 1 nanometre is 1 billionth of a metre. They are to be made of pure carbon with some additional chemical groups that will attract and trap the carbon dioxide. Once saturated with carbon, the 'used' tubes will be regenerated by a rapid heat pulse generated from a renewable energy source such as a solar cell, and the carbon dioxide will be concentrated and stored in small canisters. The researchers suggest that these canisters could then be exchanged periodically for fresh ones as part of a regular collection round. The filled carbon dioxide canisters could then be transported to a special facility where the carbon can be collected prior to secure disposal deep underground using carbon capture and storage technology. Another option is to convert the carbon dioxide into added value chemicals using novel catalytic reactions. The next step for this new innovation is to bring a patentable unit to market within the next five years. The project is set to run until April 2012.For more information, please visit:University of Edinburgh:http://www.ed.ac.uk/home
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