alt Hacker NewsEfficient method to capture carbon dioxide from the atmosphere
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Well, instead of repeating myself manually, I'll paste in a comment of mine here from a past discussion on carbon capture:
It's easy to forget why there is a bit of a challenge to getting C02 out of the air: there's so little of it, comparatively.
In order, air is, broadly, made up of the following:
Nitrogen: %78.084
Oxygen: %20.946
Argon: %00.934
CO2: %00.042
The stuff is essentially beyond a rounding error - it really gives one an appreciation of the "either don't release it, or capture it at the point of release" sentiment, and for the difficulties in making carbon capture outside of these scenarios be even slightly cost-effective.
The best carbon capture device is the ocean, and for the last 10 years or so huge amounts of free-floating sargassum seaweed have grown in warm ocean waters around the world. Nobody is certain why the sargassum has appeared in such volume lately, but it's plausible to speculate that increased CO2 in ocean water plays a role. As far as I can see the only remotely efficient way to sequester carbon at scale is to leverage the ocean by gathering the seaweed and dumping it on marginal or desert land, both to trap the carbon and fertilize the soil, thus promoting additional carbon-binding plant growth.
At current rates of emissions, we’re only about 20 years away from people needing to install CO2 scrubbers in their homes.
Soda lime, or calcium hydroxide, is the current state of the art. We use that in an anesthesia and in saltwater aquariums and in scuba rebreathers. An idealized system can capture 500 mg per gram, but in practice you only capture around 250mg/g. This outperforms the method in the article but it’s one-shot. There are interesting proposals to use this for direct capture at industrial facilities and to turn the waste material into bricks for building.
The key advantage of this new material appears to be that it can be heated and reused. That would be very valuable in an interior direct air capture use case. Think about filtering the CO2 from an office or a home to get us back to pre-industrial levels indoors.
Direct air capture imo can’t escape the scaling problem - when the feedstock has CO2 at ~400 ppm the economics simply won’t work out despite various oil companies backing one off systems around the globe.
Capturing CO2 at the source (power plant, etc) would be simpler to reach economic viability but without incentives it’s dead on arrival. I believe the IRA infra bill had put a price ~$50/ton of CO2 captured.
A better title would be "More efficient method to capture CO2 from the atmosphere." The method is not objectively efficient, but may be more efficient than other methods (solvents/sorbents) used for DAC.
Economics rules everything. How much does this cost vs simply planting trees, when the value of harvesting the trees is included? Since tree farms are generally profitable, and wood is expensive, it seems this method is likely to be economically less efficient.
This seems like the actual work of the article: https://pubs.acs.org/doi/10.1021/acs.est.5c13908
And the superbase is 1,5,7-triazabicyclo [4.3.0] non-6-ene
It is an anime based technology. Other amines in water-based solutions also get regenerated at about <200C. It is great to find new molecules to do this work but as I usual, these marketing articles sensationalize the actual work.
People need to keep in mind how rare CO2 is in the atmosphere. It currently is at around 420 ppm and was at around 100 ppm less in the 60s. CO2 is a miniscule part of the atmosphere, which is why large relative changes are caused by human activity.
To remove 10ppm of atmospheric CO2 from the atmosphere (which would do nothing to sustainably lower CO2 in the atmosphere) would require processing 10ppm of the entire atmosphere. That is one in 100.000 parts of the atmosphere. The entire atmosphere is around 5x10^18 kg, so we need to process 5x10^13 kg of air. Which is 50 million million (no typo) kilos of air.
The industrial task of doing this unfathomably large and by itself would have no long term Impact.
Human fabricated carbon capture from ambient air is a complete fools errand only promoted by the scientific illiterate or those who benefit from scientific illiteracy. You can essentially just look at the first graph on wikipedia and see that it is never going to work: https://en.wikipedia.org/wiki/Carbon_dioxide_in_the_atmosphe...
One thought I had was to go a very cold place and freeze CO₂ out of the air, about -80°C.
There’s the katabatic winds off of the glaciers in Greenland and Antarctica, which could help things go through.
But I soon realised that CO₂ is so potent, that it’s so such a small proportion of the air that not much would be taken out.
There’s some renewable storage systems that liquify air, that could remove CO₂ but they don’t mention it;,but air liquification doesn’t seem to be growing fast as an option.
The other one from mere A-level chemistry is buffer solutions and using chemical reactions in the Oceans, apart from iron seeding for life, but a chemical that precipitate an insoluble carbonate. Not ideal raining down precipitates, or using the Ocean as a test tube.
I read somewhere that electrolysis of marine water could emit enough oxygen, while also harvesting hydrogen, to counter CO2 emissions, but I can’t find the source, has anyone heard of it before or am I filling the gaps of my memory with generated garbage?
Tired of EU "nag screens" ?
Without knowing much about the details of it, this might be interesting to evaluate as a potentially economically more attractive alternative to DAC in the supply chain of e-fuel production?
It seems like the focus should be on capturing carbon dioxide from the oceans. Carbon dioxide in the atmosphere is extremely diffuse, but the oceans absorb it in large quantities and as a result it becomes much more dense which makes capture fundamentally more efficient.
Trees!
The thing people don't think about with regards to CO2 capture is that you have to get the atmosphere in order to capture CO2 from it. You essentially have to suck the entire atmosphere into these carbon capture facilities.
Using something like this to capture carbon from an exhaust pipe might be viable, but scrubbing CO2 out of the atmosphere is not even remotely viable. There's just too much air out there.
What are the use cases of CO2 appart for making my Coke fizz?
This solves only part of the problem: it captures CO2 and can release it later. But you still need to figure out what to do with this CO2, how to turn it into something useful.
Just use lye to baking soda. You could in theory make an efficient roundtrip.
Anyway - CO2 in the atmosphere is here to stay. Much more "realistic" approach is to decarbonize the ocean and let the ocean absorb the atmospheric CO2.
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I have an efficient method. It's called plants. Amazon is re-greening
I am not against doing research in this area, please do, it is interesting and likely has many applications but global CO2 removal isn't one of them. Nothing proposed, including this, is within any orders of magnitude of a viable solution. The only solution we have is put less in the air in the first place. This tech looks interesting for transporting CO2 but that doesn't mean it sequesters it and even if sequestration was solved the scales here are massive. If we don't have the political will to reduce the amount going into the air then what makes anyone think we would have the political will to build out some system to capture and sequester? We need to focus more on not putting CO2 into the air and less on trying to take it out.