Hi Folks, The search for a means to convert atmospheric (space capsule) CO2 into carbohydrates goes back to the early Apollo development era, as far as I know. Using CO2 as a food/fuel base has many obvious advantages and should be investigated for use on a global scale. The most efficient means to date seems to be through a photosynthetic bioenergy foam: *New bioenergy production platform 'Photosynthetic Foam' has been shortlisted in the Today The Earth Awards 2010 for sustainable design.*<http://www.renewableenergyfocus.com/view/11864/photosynthetic-bioenergy-foam-competes-for-us-50-000/>
"Professor Wendall explains: “*Plants typically convert solar energy into sugars at a rate of 1-5% but the foam does this at a minimum rate of 16% - and even more in some circumstances*.”." This method has the advantage of being able to adjust for differing CO2 concentrations ie. feeding rates and does not utilize high cost catalyst. I was not able to find an open source for his paper. I believe it would be worth reading in view of this nanotube development. Finding the right organic enzyme to convert atmospheric CO2 into carbohydrates, at the ppm concentrations we now see, would literally be 'mana from heaven'. Best, Michael On Tuesday, July 9, 2013 2:18:43 PM UTC-7, andrewjlockley wrote: > Article link > > http://www.ecopedia.com/environment/artificial-photosynthesis-the-future-of-carbon-dioxide-removal-in-solar-forests/ > > Paper link > http://pubs.acs.org/doi/abs/10.1021/nl401615t > > In a May, 2013 paper in NANO Letters, titled “A Fully Integrated > Nanosystem of Semiconductor Nanowires for Direct Solar Water Splitting.” > With co-authors are Chong Liu, Jinyao Tang, Hao Ming Chen and Bin Liu, > Scientists with the U.S. Department of Energy (DOE)’s Lawrence Berkeley > National Laboratory (Berkeley Lab) have reported the first fully integrated > nanosystem for artificial photosynthesis. The article is about as fun to > read as the title, but it makes a very clear point – artificial > photosynthesis is not only possible, it can potentially be done at even > greater efficiency than by the plants it is based on. The research is based > on solar cells that split water molecules and combine them with airborne > carbon dioxide to produce the simple sugar glucose and oxygen. Peidong > Yang, a chemist with Berkeley Lab’s Materials Sciences Division, explains > it like this, “The photo-generated electrons in the silicon nanowires > migrate to the surface and reduce protons to generate hydrogen while the > photo-generated holes in the titanium oxide nanowires oxidize water to > evolve oxygen molecules. The majority charge carriers from both > semiconductors recombine at the ohmic contact, completing the relay of the > Z-scheme, similar to that of natural photosynthesis.” In English, the > artificial photosynthesis cells are comprised of two sides, one made of > titanium oxide and the other of silicon. There are also a host of > co-catalysts that help the process get started. Each cell works almost > identically to a standard solar voltaic cell, but instead of using the > displaced electron to create a current, it uses the electron to chemically > adjust the structure of molecules in the cell. The photosynthesis inside > the artificial leaf structures is currently not very efficient; in fact it > is a paltry 12% efficient. That’s slightly lower than the efficiency of > plants. Up to this point, all such projects have been focused on a single > solar leaf. This is the first successful attempt at creating a viable > network of integrated leaves that act in a similar manner as trees. The > total output of the system was similar to that of a 10 ft. Maple tree. This > could be a hugely important advance in solar technology as it has the > potential to remove the need for inverters or batteries in solar > applications. The solar leaf will produce a storable energy and remove > carbon dioxide from the air. This would allow the installation of solar > leaves in areas where traditional battery storage systems are not feasible. > At the current efficiency level, it doesn’t make sense to pursue this > technology, but there are several carbon reducing catalysts that, in > theory, should be able to break the 12% threshold. The only real sticking > point in the entire artificial photosynthesis game is that artificial > catalysts are still not able to efficiently utilize carbon dioxide in the > concentrations that are currently in the atmosphere. Until researchers are > able to overcome this fundamental issue, even the most efficient carbon > dioxide transferring solar trees will not be feasible on a large scale. > > See more at: > > http://www.ecopedia.com/environment/artificial-photosynthesis-the-future-of-carbon-dioxide-removal-in-solar-forests/#sthash.PQDVflEm.dpuf > -- 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/groups/opt_out.
