How to separate CO2 into C and O2

[Jacquesl]

How to separate CO2 into C and O2, how can this be done, will this require, much energy?

 

[cesiumfrog]

heh. this is chemistry (even biology), not physics.

 

[AlphaNumeric]

Yes, it requires a lot of energy. Burning things like coal is effectively going the opposite way, C + O2 -> CO2. Then think how much power our civilisation has got and is getting from coal.

 

[trajan22]

If you can solve this then you've solved global warming. :)

 

[Gokul43201]

How to separate CO2 into C and O2, how can this be done, will this require, much energy?

Heat it, it takes 393.5 kJ/mol.

http://webbook.nist.gov/cgi/cbook.cgi?ID=C124389&Units=SI&Mask=1

 

[chemisttree]

The easiest way is to feed it to a plant. It converts the carbon to carbohydrate which can then be carbonized by heat in the absence of air or by strong sulfuric acid. Oxygen is produced when light is present.

Alternatively, you could heat CO2 over a catalyst of iron doped zeolite and hydrogen to produce water and ethylene. A nonthermal plasma applied to ethylene will generate carbon soot and recover the hydrogen. Electrolysis of water gives back the extra hydrogen and produces oxygen. (Hey! I didn't say it was efficient.) It might be useful to someone on Mars who has endless power in the form of a nuclear reactor and plenty of CO2 but not so much oxygen.

 

[Jacquesl]

Oxygen is produced when light is present.

Nice man, NASA must actually start a Amazon in the space station with dozens of trees with a sun roof on top the station for the light. And use the human waste for plant food and the water I’m not so sure yet.
What happens then plants doesn’t get CO2 ? does it die?
So just by burning some Carbon containing stuff I can make a dish of plant gasses, called CO2, and that can then me converted back to O2 and the C is absorb by the plant to make glucose, with the presence of water.

But this idea from you sounds brilliant, but like you’ve said, you will need unlimited energy for that current hungry Electrolysis

you could heat CO2 over a catalyst of iron doped zeolite and hydrogen to produce water and ethylene

If hydrogen exist 75% in space, can it be used by tapping into that source

I’m not understanding that “catalyst of iron doped zeolite”

 

[chemisttree]

Not my idea. The idea of using photosynthesis in space to produce oxygen from CO2 and water has been around a very long time. Converting CO2 to oxygen (abiotically) is currently being investigated by NASA as a source of Oxygen on the manned mission to Mars.

Zeolites are inorganic cage structures of aluminosilicates. Some synthetic varieties can be based on phosphorous and silica as well. The cage structures have sites where cations reside. Usually these cations are simply sodium or potassium but they can be exchanged for other cations such as calcium and magnesium. The cavities in the cage structure are large enough in some cases to trap and hold fairly large species. If a transition metal species is allowed to occupy some of the space, you have the potential to have a catalytic reaction site. Zeolites are used in this way (and other ways) as catalysts. The most common use for zeolites is in the form of cat litter. It seems that zeolites have an affinity to ammonia and thus minimize the odor from the litterbox. Another use for zeolite is to soften water by exchanging divalent metals (calcium, magnesium) for sodium. It is usually present in powdered laundry detergents and in that role is known as a detergent "builder".

 

[mormar]

Single a question, is not important but...

Catalyst is an substance which increases the rate of the reaction.

I think, It is important to catalize the reaction because the rate of reaction is low. We can increases the rate of reaction increases the T but this is problematic, another wished reaction cannot compete.

 

[Jacquesl]

Ok, thanks I just want to make sure I just wanted to make sure that I’m not understand the terms wrong.


“In chemistry and biology, catalysis is the acceleration (increase in rate) or slowing down of a chemical reaction by means of a substance, called a catalyst,”

Lets just leave this for NASA I’m no challenge for them on this topic

 

[haiha]

The following reaction is used in submarines to recyle CO2 and release O2:

Na2O2 + CO2 -----> Na2CO3 + 1/2O2

 

[southeng]

not considering the cost of electricity, is it possible to separate CO2 by adding only electrical energy?

 

[chemisttree]

Oxygen can be isolated but carbon monoxide is the final carbon containing product.

http://www.sbir.nasa.gov/SBIR/abstr...5-1-X9.01-8156.html?solicitationId=SBIR_05_P1

http://neptune.spaceports.com/~helm...egy1/2_5_3_utilization_martian_resources.html

 

[TripleS]

If hydrogen exist 75% in space, can it be used by tapping into that source

the hydrogen in space is spread out in a very large area, and for us to tap into nebula or other large clouds of hydrogen that isn't already in fusion..our space exporation would have to be very much better than it is at the present moment.

 

[frankferg]

How about using the Hutchison effect?

 

[Borek]

Speaking of crackpottery... you can use tweezers to separate carbon and oxide. Just pull in opposite directions.

 

[1ducky3]

I think a way to separate them is by mixing it with something else that would be like CO2 + ? --> C? + O2, and it should be something better than Carbon Dioxide, I've taught about this, and I am just getting into high school, and I am going to study chemistry for 2 years.

 

[PaulS1950]

Don't the CO2 scrubbers in re-breathers and in spacecraft use activated charcoal to capture the carbon and release the oxygen?

 

[russ_watters]

They absorb CO2, but do not release oxygen: http://en.wikipedia.org/wiki/Carbon_dioxide_scrubber

 

[chemisttree]

Don't the CO2 scrubbers in re-breathers and in spacecraft use activated charcoal to capture the carbon and release the oxygen?

They use a strong base like lithium hydroxide. It absorbs the CO2 converting it to Li2CO3.

 

[mikelepore]

Can just heating it do the job?
C + O2 --> CO2 + energy released
CO2 + energy added --> C + O2

 

[Zero :)]

i read something somewhere about 'magic mist'... the website basically promoted the mist technology claiming, in essence, that if you want to capture 100 molecules of carbon from co2, then you would need to spray them with 100 little dropletz of h2o, same sized. I am no chemist... but sound a bit to easy to be true...

what about water filtration though? wouldn't that extract the carbon?

sorry I am just curious...

 

[Eriqire]

Speaking of crackpottery... you can use tweezers to separate carbon and oxide. Just pull in opposite directions.

If you used a focused light beam (laser) it would (theoretically) be plausible (with an atomic force microscope)

 

[Gokul43201]

If you used a focused light beam (laser) it would (theoretically) be plausible (with an atomic force microscope)

This statement makes no sense. An AFM does not, for instance, shoot out a laser beam at the sample.

 

[chemisttree]

This statement makes no sense. An AFM does not, for instance, shoot out a laser beam at the sample.

It can but I don't think that laser tweezering is being performed. You can Google "AFM Tip-Assisted Optics" and see some commercial equipment that can perform Raman spectroscopy (which uses a laser) during an AFM scan.

 

[Gokul43201]

Yes, I guess it's hardly inconceivable that one could piggy-back an optical system on an AFM to rig a Scanning Raman Microscope.

But it's still a stretch to go from optical tweezers to breaking covalent bonds. The problem is not the positioning accuracy (which even an AFM might not be able to help with), but I suspect it will be the field gradient that would be required to break a C-O bond. Or is this something that people have done?

 

[chemisttree]

Good point. I have no idea but I seriously doubt it.

 

[Eriqire]

This statement makes no sense. An AFM does not, for instance, shoot out a laser beam at the sample.

Use the AMF to figure out how to project the light through a series of half-silvered mirrors and lenses. Also, light has enough power to move things at a microscopic level. It is the same principal used in microwaves only focused.

 

[eextreme]

An experimental idea. Put CO2 in a large (strong container with pipes to go two different containers) and send a high voltage through the gas and see what happens. Any idea what will happen?

 

[DrStupid]

Oxygen can be isolated but carbon monoxide is the final carbon containing product.

How about the Boudouard reaction as a second step:

1. 2 CO₂ -> 2 CO + O₂
2. 2 CO -> CO₂ + C

 

[chemisttree]

How about the Boudouard reaction as a second step:

1. 2 CO₂ -> 2 CO + O₂
2. 2 CO -> CO₂ + C

Sure, if your goal is to produce carbon. The carbon would likely foul the catalyst though and since the Martian atmosphere has plenty of CO2 already, there is no advantage to the second step IMO. The design of the reactor might need to be such that this reaction is prevented from happening.

 

[DrStupid]

Sure, if your goal is to produce carbon.

According to the title of this thread it is.

 

[chemisttree]

According to the title of this thread it is.

Of course it is but you were responding to my post which featured links where the final carbon-containing species was CO (as I indicated).

 

[DrDu]

In radiocarbon dating one reduces carbon dioxide e.g. with iron and hydrogen gas to elemental carbon. You could freeze out the water formed in that process from the hydrogen stream and separate it by electrolysis. Net result would be the analysis of carbon dioxide into carbon and oxygen.

 

[DrStupid]

Of course it is but you were responding to my post which featured links where the final carbon-containing species was CO (as I indicated).

And because CO is only half the way to carbon I suggested a second step to complete the separation of CO₂ into C and O₂.