can someone tell me y the carbon in co2 can't just be extracted as a solid?

[mopinko]

i don't remember my chemistry well enough to have a clue about this, although i am sure i should.
but i was reading redqueen's thread about science v climate change, and it brought up a question that i have had before-
all the plans for dealing with co2 seem to involve trapping and storing it as a gas. i suppose the answer is energy consumption, the laws of physics being what they are. but it sure seems like it would be easier to store elemental carbon than that storing large quantities of gas.
thought? besides- mopinko, i think you are an idiot, get back under your rock.

[tridim]

1. That's what plants do.

[MineralMan]

3. Botany 101

[mopinko]

13. yeah, i know that, and

honestly, i am still a little pissed at bill clinton and al gore for not starting a massive program to plant trees around the world. i mean, where is the downside?

[Vincardog]

2. IT takes a LOT of energy to make diamonds

[doc03]

4. Don't know good question n/t

[tabatha]

5. I read somewhere a year or so ago

about someone proposing to do just that.
I'll see if I can google it.

[timeforpeace]

6. This points out precisely why global warming science is so popular.

[tabatha]

7. Here it is in wiki

Carbon, in the form of CO2 can be removed from the atmosphere by chemical processes, and stored in stable carbonate mineral forms. This process is known as 'carbon sequestration by mineral carbonation' or mineral sequestration. The process involves reacting carbon dioxide with abundantly available metal oxides–either magnesium oxide (MgO) or calcium oxide (CaO)–to form stable carbonates. These reactions are exothermic and occur naturally (e.g., the weathering of rock over geologic time periods).<42><43>

CaO + CO2 → CaCO3

MgO + CO2 → MgCO3

In nature calcium and magnesium are found typically as calcium and magnesium silicates (such as forsterite and serpentinite) and not as binary oxides. For forsterite and serpentine the reactions are:

Mg2SiO4 + 2CO2 = 2MgCO3 + SiO2

Mg3Si2O5(OH)4+ 3CO2 = 3MgCO3 + 2SiO2 + 2H2O

The following table lists principal metal oxides of Earth's Crust. Theoretically up to 22% of this mineral mass is able to form carbonates.

Earthen Oxide Percent of Crust Carbonate Enthalpy change
(kJ/mol)
SiO2 59.71
Al2O3 15.41
CaO 4.90 CaCO3 -179
MgO 4.36 MgCO3 -117
Na2O 3.55 Na2CO3
FeO 3.52 FeCO3
K2O 2.80 K2CO3
Fe2O3 2.63 FeCO3
21.76 All Carbonates

These reactions are favored at low temperatures.<42> This process occurs naturally over geologic time frames and is responsible for much of the surface limestone. The reaction rate can be made faster, for example by reacting at higher temperatures and/or pressures, or by pre-treatment of the minerals, although this method requires additional energy.

CO2 naturally reacts with peridotite rock in surface exposures of ophiolites, notably in Oman. It has been suggested that this process can be enhanced to carry out natural mineralisation of CO2.<44><45>

http://en.wikipedia.org/wiki/Carbon_sequestration

[zipplewrath]

8. Energy

It "can" be done, but the amount of energy required to do that is not inconsequential. Most "carbon capture" technologies use some form of plant/bacteria based method to do it, and they "feed" the bacteria and usually have to expose it to sun light. I've thought on occasion that one could probably create the "pet rock" of the green movement if they could create a simple, solar powered, desk top machine to extract carbon from CO2 as a novelty. Not that it would represent any real carbon reductions, just sorta the equivalent of a "learning toy" or something.

[HereSince1628]

9. Here's a review of the chemistry of carbonate sequestration

http://arjournals.annualreviews.org/doi/abs/10.1146/annurev.energy.27.122001.083433

[mopinko]

11. sorry, not spending $20.

thanks, tho

[HereSince1628]

15. The Left (!) always want everything for free.

Just KIDDING!!!!!!!!!!!!

I hate pay sites, too. But, I also understand the publishing issues for relatively small audiences.

[mopinko]

17. i'm sure it is worth it to many people

but yeah, the left does always want stuff for free!

[Dogmudgeon]

10. All it takes is energy

Lots and lots of energy.

--d!

[mopinko]

12. now, didn't i say that in my op?

lots and lots is not really the kind of answer that is worth the bandwidth in the science forum. don't mean to be snarky, just....

[Orsino]

14. It is the key problem.

All that free energy we got from a million years of willy-nilly combustion has to be paid back. Mother nature has managed to sequester some of it, but in the last couple of centuries we have left Her far behind.

We can't meet all our perceived energy needs now. How the hell do we undertake a do-over of all of human history as well?

[mopinko]

18. oh, that much i remember.

conservation of energy and all that. algae is my favorite solution so far. solar power of some sort is undoubtedly necessary.
i still don't know why we are not harvesting the awesome chemical power of pig shit, but that is another thread.

[Dogmudgeon]

16. Well, yeah ...

But you'd be surprised at how many people have magical ideas about energy.

Well, maybe you wouldn't. But I am, every time I confront it.

When I was about seven years old (in 1965), I proudly told my parents that I had made an incredible invention -- that if you just put a fan on a sailboat, and pointed it at the sail, and powered the fan by dragging a turbine, you would have an inexhaustible source of energy.

I recall laughing about it when I realized how absurd an idea it was. About six hours later, when my Dad took me to the library that evening and pointed me toward the "Science-4-Kidz" section.

Two years later, I built a solar cell from a strip of lab-tempered copper and a jar of fruit juice electrolyte. I think I got about one ten-thousandth of an amp (more than the baseline) out of it when it was in the sunlight.

My Dad then suggested that uranium in a reactor was a lot more efficient at producing energy -- which has led to no end of trouble on progressive websites!

:)

--d!

[NNadir]

19. The answer is the same as the that which answers the question, "Why can't we just desalinate...

...the ocean whenever there's a drought."

The answer is "Energy."

An attempt to reduce carbon using the energy supplied by dangerous fossil fuels would constitute a perpetual motion machine.

If one uses another form of energy, say nuclear energy, it is possible to do it.

[mopinko]

20. i'm shocked, shocked i tell you

to hear you say that nuclear is the answer.

[NNadir]

21. I have given A LOT of thought to reducing carbon dioxide, more than I can tell.

Nuclear energy is the only form of energy with sufficient energy/mass density to do it.