Earth doesn't have an energy problem; the Earth has an energy carrier problem

January 6, 2012 8:15 PM

Alain Goeppert, G. K. Surya Prakash, chemistry Nobel Laureate George A. Olah and colleagues have co-authored a paper (doi: 10.1021/ja2100005) in the Journal of the American Chemical Society describing a novel, cheap material that scrubs CO2 from ambient air, even at the very low concentrations of the atmosphere. The material is easily manufactured, and carbon captured is readily removed from the polymer, allowing recycling of the polymer and sequestration of the carbon. The researchers, co-authors of Beyond Oil and Gas: The Methanol Economy regard this as more than simply a technique for decreasing the carbon emissions of industrial processes and fossil-fuel burning machines, but as possibly an energy-carrier, by using the "catalytic hydrogenation of CO2 with H2 where the hydrogen has been obtained from water electrolysis (wiki). Articles: ScienceDaily, SciAm.
posted by bumpkin (29 comments total)

Sounds like an all-around win to me. We can use solar power for the electrolysis part. Make it so, Number One.
posted by anigbrowl at 8:36 PM on January 6, 2012

oooooh, dang. I'm going to read the heck out of this paper
posted by zomg at 8:53 PM on January 6, 2012

Olah's an amazing chemist, and this is well thought out, but methanol is just a way of storing energy....

(.....No one is seriously suggesting that we could scrub enough CO2 from the atmosphere to put a dint in the quantities we release.....right?.....)

To get CO2 + H2 -> CH3OH +H2O requires energy

from the wiki

The energy needed for these reactions in order to be carbon neutral would come from renewable energy sources such as wind, hydroelectricity and solar as well as nuclear power...

Once again, we're back to the cut. We need to invest iraq-war, moon-landing, 20% of GDP, 8th branch of armed forces, new arm of govt scale efforts in renewables now, or our goose will cook too quickly.
posted by lalochezia at 9:02 PM on January 6, 2012 [10 favorites]

Polyethylenimine, the material in question, appears to be "very strong toxicity", "extremely cytotoxic", and "the disruption of the cell membrane leading to necrotic cell death (immediate)". I don't know what that means but this material is apparently cheap, 100 grams for $60 or so w/ bulk discounts at world saving quantities.

lalochezia, I think the central idea is to collect carbon passively using Polyethylenimine from smokestacks and car exhausts and even directly from the air which doesn't require energy input.
posted by stbalbach at 9:08 PM on January 6, 2012

stbalbach, that seems to be for linear polyethylenimine, in the context of cell based studies. I don't think you can generalize to all types of polyethylenimine, especially not on whole organisms or the environment. The size, branching and breakdown potential for the polymers are all going to greatly influence potential toxicity/environmental impact.
posted by Orange Pamplemousse at 9:46 PM on January 6, 2012

lalochezia's point is well-taken. The reaction is endothermic, it takes in energy - that means that there has to be some sort of energy input to make it go, and that left to its own devices, the reaction will tend to go the other way, "passive" or not - and their website agrees.

> (.....No one is seriously suggesting that we could scrub enough CO2 from the atmosphere to put a dint in the quantities we release.....right?.....)

That's "dent", not "dint". Scrabble is an unfortunate guide here as you don't have to know the meanings to play well... :-P

Well, you do have the expertise here, and I would defer to you that there's no current chemistry that would do it (and we'd probably have heard of it), but it's not a priori impossible, is it? Some catalyst such that CO2 + H2 + sunlight + catalyst -> CH3OH + H2O could conceivably exist, right?

In fact, since I have you online, might I ask - it has always been in the back of my mind that if we had "perfect" control of nanotechnology, we could create any catalyst for any reaction we liked - simply by arranging some structure that "put the molecules in the right geometric arrangement". Is this correct?
posted by lupus_yonderboy at 9:48 PM on January 6, 2012

stbalbach, pricing on chemicals is more complicated than you suggest. For example, I have a 500 quantity jar of 200mg ibuprofen tablets in my medicine cabinet that cost me about $6 (for total of 100g of ibuprofen). From your source that would cost me (not including any pharmaceutical-grade fillers and buffers) as much as $3300.
posted by peeedro at 9:48 PM on January 6, 2012

> and their website agrees.

or rather, lalochezia's quote from the site agrees - unfortunately as a mortal I can't see it.
posted by lupus_yonderboy at 9:49 PM on January 6, 2012

I briefly looked over the paper. Couple of key points:

• The authors state the adsorption capacity is around 1-2 mmol CO2/g. This far lower than competing non-polymer solid adsorbents for CO2. Typical values for zeolite-based adsorbents are 6-7 or higher mmol CO2/g. The research is novel in that polymers are being used, but it is certainly not a step change in how these adsorbents behave. In fact, the amine based adsorption chemistry is identical to non-polymer aBsorbption processes.
• The kinetics of adsorption appear to be a slow, the adsorption half-time is on the order of 10-12 hours. This combined with the low carrying capacity means doing this on any large scale will require very large amounts of adsorbent or high flow rates in a fluidized system to be competitive with existing solutions.
• The low regeneration temperature is interesting, but probably explains the slow kinetics.

My overall feeling is that it's a novel polymer-based approach for CO2 capture and worthy of publication. But it is not revolutionary, by any means.
posted by kproto at 9:51 PM on January 6, 2012 [2 favorites]

I'm not being fliippant here, but how is this better than planting a tree?
posted by empath at 9:58 PM on January 6, 2012 [4 favorites]

or rather, lalochezia's quote from the site agrees - unfortunately as a mortal I can't see it

The quote is from the Wikipedia link in the FPP. You plainly have no idea what you are talking about. The carbon capture aspect of the compound requires only ambient heat on the order of 45° C, easily found in a smokestack or exhaust pipe. The synthesis of the compound essentially involves dissolving PEI in methanol, mixing it with fine sand in a second methanol solution, and letting the methanol evaporate off. You could safely make it in your backyard, probably, as long as you didn't have any naked flames around.
posted by anigbrowl at 10:06 PM on January 6, 2012

how is this better than planting a tree?

You don't have to wait a decade for it to start working, I think. The nice thing about this is that it's cheap and works at ordinary temperatures. Cheap matters a lot.
posted by anigbrowl at 10:11 PM on January 6, 2012

> You plainly have no idea what you are talking about.

Perhaps I do not. lalochezia, on the other hand, is a chemistry professor, so I'll defer to him over some random rude person on the internet.
posted by lupus_yonderboy at 10:18 PM on January 6, 2012 [2 favorites]

You seem to think I'm disagreeing with him him, which is not the case.
posted by anigbrowl at 10:43 PM on January 6, 2012

Just for a reality check, 2010 estimated CO2 emissions (in thousands of CO2 metric tonnes).

Considering that we are going to be scrambling to find enough carbon-neutral sources to maintain existing energy demands for things like food and medicine in the next 20 years, I think it's a long off pipe dream that we'll have 3 billion tonnes of extra H2 produced per year, in a carbon neutral manner, just to convert existing CO2 emission streams to methanol. You're better off just using the renewable energy to replace the fossil fuels in the first place.
posted by benzenedream at 10:45 PM on January 6, 2012 [2 favorites]

...carbon captured is readily removed from the polymer, allowing recycling of the polymer and sequestration of the carbon.

capturing CO2 is not the challenge.
Carbon Sequestration is the challenge.
permanent sequestration of CO2 is theoretical, rather like permanent storage of nuclear waste.
Planting a tree does result in a solid and fairly durable form of carbon, unfortunately CO2 collection.
Sadly, the world is no more interested in increasing biomass cover than it is in decreasing the rate of fossil carbon combustion.
posted by Abinadab at 10:47 PM on January 6, 2012 [5 favorites]

Planting a tree does result in a solid and fairly durable form of carbon, unlike CO2 collection.
posted by Abinadab at 10:54 PM on January 6, 2012

Yes, but it's still slow and impermanent, so there is plenty of room for other technology in addition to (not instead of) planting more tree.
posted by anigbrowl at 11:25 PM on January 6, 2012

You also have to do something with the tree at the end of its life other than burn it.
posted by BrotherCaine at 12:54 AM on January 7, 2012

You also have to do something with the tree at the end of its life other than burn it.

Mulch for growing more trees.
posted by Blazecock Pileon at 1:45 AM on January 7, 2012

You're better off just using the renewable energy to replace the fossil fuels in the first place.

I think stuff like this is an attempt to more actively remove existing CO2 from the atmosphere and, by converting the the CO2 to methanol, it's solving a storage problem. Even if we can generate all of our energy with non-fossil fuel sources, at present batteries suck as a storage medium compared to gas, diesel, ethanol, methanol, etc. This would allow us to use fossil fuel alternatives for everything but our cars and our cars would run on methanol as well as being a backup to power plants for when the sun goes down or the wind stops blowing.
posted by VTX at 6:17 AM on January 7, 2012

Thanks for the chemists and material scientists piping up. That's not my background: I'm a geologist, and having not found much commentary on the article, was hoping to learn something from the discussion here. Indeed, as far as CCS goes, I know a good deal about the 'S' part, and much less about the 'C'.

This, for example, is exactly backwards:
capturing CO2 is not the challeng,e.
Carbon Sequestration is the challenge.

Geological carbon sequestration is a mature science, with few technical challenges. The 'capture' part of it however, is tricky because I have yet to see approaches for small distributed sources (like, say, cars), and even in single large emitter installations (say, a coal plant), it necessarily imposes burdens of added considerably design complexity and lowering the useful energy yield (which translates to added dollar cost).
posted by bumpkin at 6:26 AM on January 7, 2012

Let's separate 2 things out

a) CO2 capture (getting CO2 from the atmosphere)
and
b) CO2 as a feedstock (converting CO2 to a high energy molecule)

For CO2 capture


i) CO2 capture would need to be done on a vast scale. The idea of having some kind of recycler based on this PEI system in a smokestack using ambient temperature to power it is interesting but I'd need to see how it scaled, both in terms of engineering and production of the sequestering agent. Using waste heat is a neat idea, but what I've heard as an informed non-expert is that these technologies are mighty expensive, and to run require energy greater than the low grade waste heat from powerplants have

Where do we get that energy from?

ii) To pump that CO2 into some sort of storage requires energy

Where do we get that energy from?

For CO2 as feedstock

ii) If the idea is to convert of CO2 to Methanol (which we could later use as energy storage, burn, releasing CO2 again*) or use a feedstock to make things (larger molecules), the problem is that the both the conversion reaction and the generation of raw supply materials require energy.

CO2 is at the bottom of a very long thermodynamic gradient from C and O2. There's a reason why it's the terminal product of virtually all oxidation processes using carbon: it's very stable - low energy. In order to covert it back to a high energy compound like methanol, we must a) make H2 or a reducing equivalent - requiring energy and then b) supply energy to the system to go 'up the hill' - requiring energy.

Where do we get that energy from?

All of these processes require energy. The catalyst that lupus mentions would allow us to speed up the reaction so that CO2 consumption would occur at a reasonable rate. This saves some energy as we wouldn’t have to heat the system to get the reaction to go fast enough to be useful, but there is NO getting around the fact that you have to put energy in order to drive the reaction to CH3OH.

Trees and plants do this with photosynthesis, probably one of the more efficient and elegant and beautiful physical processes there is in the universe. However, trees and plants grow slowly - or at least slowly on the scale we want for carbon sequestration and biomass production - there is no natural system that uses ambient light to quickly sequester CO2 and drive the generation of high-energy compounds at the rate we want. The only way to make this happen quickly is to have bucketloads of energy around.

Where do we get that energy from?

We need solar or wind or geothermal or another renewable on a vast scale, and we need it now.

There will come a point in the where our societies simply won't have the physical resources and capability to make industry to manufacture this capacity on the scale needed. The clock is ticking: we're burning our clothes, food and medicine to keep warm; our primary activity as a species appears to be squabbling over the type, color and moral appropriateness of each other’s jewelry.



* No free lunch etc.
** Ignoring the obvious lack of political capacity.

posted by lalochezia at 7:07 AM on January 7, 2012 [12 favorites]

Blazecock Pileon writes ""Mulch for growing more trees."

Mulching trees is just a way of slowly burning the tree. One needs to store the tree forever to truly sequester the carbon.
posted by Mitheral at 8:28 AM on January 7, 2012

The only sure way to sequester carbon long-term is to "mineralize" it, convert it to carbonates, rocks. That removes it almost entirely from the carbon cycle.

There's debate at the moment as to how to count trees and forests in the carbon budgets. Lots of countries (Canada, Scandinavia) want carbon credits for planting forests. The consensus as I understand it, however, is that forests are carbon neutral, assuming a relatively constant biomass. Sustainable forestry implies this: harvesting about what is planted.

Methanol, btw, is really not a very desirable fuel. It's almost a direct gasoline replacement in terms of storage and combustion characteristics, but that comes with some very large downsides. It would require much better engine, storage and transport engineering. Few plastics and no rubbers are compatible with it. Many plastics degrade, crack, swell and turn to mush in contact with methanol. It's hell-on-wheels as a spill: high vapour pressure, high flammability, high toxicity, water-soluble. Impossible to contain, spills will have to be let to take their course, with very few technologies available for containment post-release. It does breakdown relatively quickly however.
posted by bonehead at 9:25 AM on January 7, 2012 [2 favorites]

Methanol? WTF? A truly useful process would create ethanol.
posted by Samuel Farrow at 10:47 AM on January 7, 2012

The consensus as I understand it, however, is that forests are carbon neutral, assuming a relatively constant biomass.

Yes, that is a bit of a tautology there. If the trees don't grow and you don't plant new forests, the biomass doesn't increase. So that's why the plan would be to restore natural forests and grow new trees, which would in fact increase in biomass. That would not be carbon neutral, unless the carbon cost of planting the trees and supplying them nutrients (assuming that is necessary) offsets the tree biomass. Which is an interesting question. But forest growth is not carbon neutral in of itself. It does result in sequestration, so long as the wood does not decompose from burning or something.

An important distinction to make here (and probably what you were actually getting at) is that tree farms (in the sense of those used for pulp or lumber, etc) are likely to be not carbon neutral in a bad way. In part it's because of the carbon cost of all the support infrastructure for the tree farm (lots of things painted yellow, lots of pesticides, herbicides, fertilizers), and in part because agricultural ecosystems don't usually have a thriving diverse community and don't sequester carbon in the soil - natural and in particular old growth forests have a lot of biomass and non-living carbon tied up in the soil and in the other species in the community that persists from year to year. So when you're talking about forests, you have to distinguish between forest restoration (natural) and tree-farm (agricultural) systems wrt carbon sequestration.

tl;dr: Real forests when growing do sequester carbon, unlike agriculture.
posted by zomg at 12:52 PM on January 7, 2012 [2 favorites]

Methanol? WTF? A truly useful process would create ethanol.

Some are researching methanol-to-ethanol synthesis pipelines. So the output of this would be one step in a reclamation cycle. The researchers for this paper wrote a sentence that struck me as insightful:

Instead of considering CO2 as a problematic and unwanted combustion byproduct, it should be seen as a valuable feedstock for the production of fuels and materials.
posted by Blazecock Pileon at 7:51 PM on January 7, 2012

What kproto said - apart from the polymer/silica hybrid aspect this isn't exactly new. For example ceria has recently received attention for potential direct conversion of (solar-)thermal energy and CO2/H2 to useful fuels.
The polymer/silica thing is cool, 'tho - I've worked with polyamine/silica nanocomplexes: they're interesting materials, it's easy to obtain a wide range of properties for the silica substrate and the polycation/silica bonding step is trivial. Fumed silica is the pig-iron of nanosilica research, I'm sure people are already working on something more appropriately structured.
posted by overyield at 7:42 AM on January 8, 2012 [2 favorites]