Breakthrough In Artificial Photosynthesis Captures CO2 In Acetate

An anonymous reader writes: Researchers from Berkeley Lab and the U.S. Dept. of Energy have created an artificial photosynthetic process that capture carbon dioxide in acetate, "the most common building block today for biosynthesis." The research has been published in the journal Nano Letters (abstract). "Atmospheric carbon dioxide is now at its highest level in at least three million years, primarily as a result of the burning of fossil fuels. Yet fossil fuels, especially coal, will remain a significant source of energy to meet human needs for the foreseeable future. Technologies for sequestering carbon before it escapes into the atmosphere are being pursued but all require the captured carbon to be stored, a requirement that comes with its own environmental challenges. ... By combining biocompatible light-capturing nanowire arrays with select bacterial populations, the new artificial photosynthesis system offers a win/win situation for the environment: solar-powered green chemistry using sequestered carbon dioxide."

Comments

They're called trees.

[jdharm]

"...solar-powered green chemistry using sequestered carbon dioxide." Trees. Quit cutting them down. Plant more. Problem solved.

Re:They're called trees.

[gtall]

That's not sophisticated enough. The problem is we're taking eons of sequestered carbon and dumping it into the atmosphere all at once. Trees only sequester carbon for about 100 before they're broken down into CO2 and other stuff again. Think of it as time dilated burning. And planting the world over with trees cannot possibly capture all the sequestered CO2 we're dumping.

Re: They're called trees.

[Anonymous Coward]

Oh, but it does solve the problem a bit. The old trees die and decompose, most of that organic matter sticks around long enough to be used by the next generation of plant, fungus, and animal. The soil is in turn enriched which supports more life that it previously could which in turn sequesters more carbon. It may be a pyramid scheme, but it is one that has worked for a very long time. Also, if enough organic matter is present it might actually recreate the fossil fuels that caused the problem in the first place completing the cycle (albeit in the distant future).

Re: They're called trees.

[DigiShaman]

Not cutting down the trees is a useful step, because mature growth fixes more CO2 than new growth.

You're not thinking long-term. Eventually the trees will die, decompose, and go back into the system as CO2. No, what you want to be doing is cutting down trees after their maximum growth rate has been achieved, then sequester the logs someplace. Clearing old growth makes room for newer faster growing trees that will soak up more CO2 than if you left old growth in its place. The only advantage of that (leaving old growth behind) is a more stable ecosystem as it would render that area less disturbed.

Re: They're called trees.

[sillybilly]

Yeah, but what you are forgetting is topsoil depth is pretty lacking around the world, and when trees die, decay and go back into the global carbon cycle, a portion of them is converted into usable fertile black humus rich topsoil, which is undigestable to even the top digesting lifeforms. Topsoil by far is the ultimate form of carbon sequestration, and also the source of underground coal after millions of years if it undergoes tectonic heat and molten lava silicate phase separation.

On another note, the diagram these scientists give requires two photon captures, one for generating a proton and oxygen, and a 2nd that generates acetate from proton and CO2. This may be the most efficient, hard to tell, but I expected one stage for photon capture that generates temporary chemical energy, and another stage that converts that chemical energy consuming CO2 into acetate, without requiring a 2nd photon capture. Ocean floor volcanic eruption environments have bacterial lifeforms and a whole ecosystem fueled by not the Sun, like the rest of life on planet, but the internal heat of the Earth. These creatures live in absence of sunlight completely and they are based on a sulfur based high energy low energy state chemical cycle. As a crude adaptation one might just have a concentrating solar power collector and a sample of the biosphere from such an environment with water recirculated near the "volcanic eruption hot zone" in a solar concentrator, and cooled to the other zones where these lifeforms live, and there you go, you have a solar based CO2 captturing station, but quantum efficiency would probably be low. However that sulfur cycle could be used as a starting point to create something where the solar capturing stage can be separated from the bacterial farming stage, such as bacteria living in huge underground ponds aerated with CO2 (possibly captured via ethanolaminej or something untouched by the lifeforms in a massive downdraft solar tower) and the light collection sections could take up all the real estate, moreover they could be super high temperature if needed, where reaction rates are faster possibly giving better quantum efficiencies too.

That's my 2 cents.

"Artificial photosynthesis" is misleading

[MrVictor]

If I am understanding TFA correctly, this would be more aptly titled "solar powered electrolysis apparatus to feed oxygen to acetate-secreting bacteria on a nano-wire substrate". Bad science journalism. This will not save the world.