This sounds like it could be the basis for a respirator-like breathing apparatus, not requiring tanks, for entering and staying in enclosed spaces where the concentration of CO2 is high. (Provided there is enough oxygen.)
And the "device" is called a 'rebreather.' https://en.m.wikipedia.org/wiki/Rebreather
Just think about it, you have a decorative box in your office that absorbs CO2, would it slow the inevitable cognitive decline that happens when you close your door in your poorly ventilated room?
The outdoor level has absolutely risen, it's just not the important factor here.
You're very lucky that you can keep windows open so often. My climate makes that impossible for much of the year; I'm looking in to getting an ERV installed asap.
Moreover, those buildings likely now have much less air exchange than when designed now that they use AC instead of open windows, forced air heat instead of unsealed fireplaces (which turn over a lot of air), and possibly have been updated to more airtight doors and windows.
A half a pound of powder as lovely as a tree. -- Joyce Kilmer
It doesn't really talk about how you would sequester the gaseous CO2 other than "put it underground."... But if you put a gas underground it will eventually leak out. Even a liquid is prone to leak out eventually due to plate techtonics, but a liquid doesn't immediately turn into gaseous CO2.
So though a crucial technology, I don't see how effective it would be in a long term solution.
Carbon is about 3/8ths of the total weight of a CO2 molecule and is solid and relatively inert at room temperature and pressure.
Of course, if there were a convenient way to simply strip carbon off of a CO2 molecule to begin with that would be the ideal system, but I'm sure that can be figured out given enough opportunity.
Plants do it, after all. It's not impossible.
The problem is that to reverse CO2 -> C + O2 you need the same amount of energy that you get burning coal C + O2 -> CO2.
But burning coal, like half of the energy is lost as unuseful heat.
The reaction of plants is different, but plants only has a 2% of efficiency. The chemical reaction of plants is more complicated, so let's be optimistic and assume this reaction has a 10% of efficiency.
If they use a coal plant to power the CO2 -> C + O2 conversion, they will release like 20 times the amount of CO2 absorbed.
If they use a renewable source, it's better to close the absortion plant and also 20 coal plants.
Until we close all the coal plants and we get very cheep carbon-free energy, it's bad for the environment to try a CO2 -> C + O2 conversion.
From the page https://chemistry.stackexchange.com/questions/915/how-can-ca...
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React carbon-dioxide with hydrogen in the Sabatier (https://en.wikipedia.org/wiki/Sabatier_reaction) process to get methane. 400 °C, high pressure and Nickel catalyst needed. The process is slightly exothermic so it can keep going on its own:
CO2+4H2→CH4+2H2O
This process have been proposed to generate fuel on Mars, and used on the ISS to process exhaled carbon-dioxide.
Split the resulting water (use electrolysis or some other thermochemical cycle) take the oxygen, bring the hydrogen back to Step 1:
2H2O→2H2+O2
Electricity for this may come off solar panels.
Methane decomposes at high temperatures. The process goes to completion around 1200°C. Collect the condensed carbon, bring the hydrogen back to step 1.
CH4→C+2H2
This process is proposed as an emissions free alternative to produce hydrogen from natural gas. Heat may come from concentrated solar light.
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The missing ingredients are excess CO2 from the atmosphere and a machine system to do the full process with, and of course the math about economies of scale regarding how fast a machine that uses this method combined with the powder in the article can actually strip carbon from CO2 in the atmosphere.
It likely would neither be cheap nor fast, but since it uses nickle as a catalyst at least it is not fancy rarefied expensive hard to find materials, just more an issue of getting all of the parts together and making the whole machine run as efficiently and effectively as possible.
Also, if the methane is generated from CO2, then burning it is nearly carbon neutral, so in places where fossil fuels are the ideal energy source it would allow us to use Green energy to make transportable low-carbon fossil fuels for them to use.
All of these “can’t we just unburn burnt things” forget that the reason we burnt the carbon in the first place was to get that energy.
Unburning it would need to return that energy and more because of inefficiencies.
If you have energy to spare, you don’t need to burn the carbon in the first place.
With global fossil fuel usage still rising, we clearly don’t have any to spare.
[1] https://www.technologyreview.com/2021/07/14/1028461/solar-va...
I wonder if there is a reason you couldn't just sequester the powder. Probably too expensive? Or not volume efficient?
>to leak out eventually due to plate techtonics
This might seem shortsighted, but I'm OK pushing the problem out by 50 million years or so.
The other day I was wondering how people always talk about sending undesirable material (garbage, spent radioactive fuel, etc.) on a one way trip to the sun. Why not send things to the surface of Venus? It has an ultra dense atmosphere that pulverizes anything that reaches the surface. In the case of this material, it's just more C02, which is what the atmosphere of Venus is already primarily composed of. We aren't going to ever explore the surface of Venus, or at least we won't for thousands, if not millions of years, barring we can easily convert co2 into energy, so is this a bad idea?
35 billion metric tons.
What's your back of the envelope energy figure for extracting that weight of a gas from the atmosphere, pressurising it, and lifting it to orbit and sending it to Venus?
Got a rough notion of the number of trips, fuel and resources that would need every single year?
