Carbon dioxide 'sponge' could ease transition to cleaner energy

Aug 10, 2014
Plastic that soaks up carbon dioxide could someday be used in plant smokestacks. Credit: American Chemical Society

A sponge-like plastic that sops up the greenhouse gas carbon dioxide (CO2) might ease our transition away from polluting fossil fuels and toward new energy sources, such as hydrogen. The material—a relative of the plastics used in food containers—could play a role in President Obama's plan to cut CO2 emissions 30 percent by 2030, and could also be integrated into power plant smokestacks in the future.

The report on the material is one of nearly 12,000 presentations at the 248th National Meeting & Exposition of the American Chemical Society (ACS).

"The key point is that this polymer is stable, it's cheap, and it adsorbs CO2 extremely well. It's geared toward function in a real-world environment," says Andrew Cooper, Ph.D. "In a future landscape where fuel-cell technology is used, this adsorbent could work toward zero-emission technology."

CO2 adsorbents are most commonly used to remove the gas pollutant from smokestacks at power plants where fossil fuels like coal or gas are burned. However, Cooper and his team intend the adsorbent, a microporous organic polymer, for a different application—one that could lead to reduced pollution.

The new material would be a part of an emerging technology called an integrated gasification combined cycle (IGCC), which can convert into hydrogen gas. Hydrogen holds great promise for use in fuel-cell cars and electricity generation because it produces almost no pollution. IGCC is a bridging technology that is intended to jump-start the hydrogen economy, or the transition to hydrogen fuel, while still using the existing fossil-fuel infrastructure. But the IGCC process yields a mixture of and CO2 gas, which must be separated.

Cooper, who is at the University of Liverpool, says that the sponge works best under the high pressures intrinsic to the IGCC process. Just like a kitchen sponge swells when it takes on water, the adsorbent swells slightly when it soaks up CO2 in the tiny spaces between its molecules. When the pressure drops, he explains, the adsorbent deflates and releases the CO2, which they can then collect for storage or convert into useful carbon compounds.

The material, which is a brown, sand-like powder, is made by linking together many small carbon-based molecules into a network. Cooper explains that the idea to use this structure was inspired by polystyrene, a plastic used in styrofoam and other packaging material. Polystyrene can adsorb small amounts of CO2 by the same swelling action.

One advantage of using polymers is that they tend to be very stable. The material can even withstand being boiled in acid, proving it should tolerate the harsh conditions in where CO2 adsorbents are needed. Other CO2 scrubbers—whether made from plastics or metals or in liquid form—do not always hold up so well, he says. Another advantage of the new adsorbent is its ability to adsorb CO2 without also taking on water vapor, which can clog up other materials and make them less effective. Its low cost also makes the sponge polymer attractive. "Compared to many other adsorbents, they're cheap," Cooper says, mostly because the carbon molecules used to make them are inexpensive. "And in principle, they're highly reusable and have long lifetimes because they're very robust."

Cooper also will describe ways to adapt his microporous polymer for use in smokestacks and other exhaust streams. He explains that it is relatively simple to embed the spongy polymers in the kinds of membranes already being evaluated to remove CO2 from power plant exhaust, for instance. Combining two types of scrubbers could make much better adsorbents by harnessing the strengths of each, he explains.

Explore further: Transforming hydrogen into liquid fuel using atmospheric CO2

More information: Title: Swellable, water-tolerant polymer sponges for carbon dioxide capture

Abstract
To impact carbon emissions, new materials for carbon capture must be inexpensive, robust, and able to adsorb CO2 specifically from a mixture of other gases. In particular, materials must be tolerant to the water vapor and to the acidic impurities that are present in gas streams produced by using fossil fuels to generate electricity. We show that a porous organic polymer has excellent CO2 capacity and high CO2 selectivity under conditions relevant to precombustion CO2 capture. Unlike polar adsorbents, such as Zeolite 13x and the metal-organic framework, HKUST-1, the CO2 adsorption capacity for the hydrophobic polymer is hardly affected by the adsorption of water vapour. The polymer is even stable to boiling in concentrated acid for extended periods, a property that is matched by few microporous adsorbents. The polymer adsorbs CO2 in a different way from rigid materials by physical swelling, much as a sponge adsorbs water. This gives rise to a higher CO2 capacities and much better CO2 selectivity than for other water-tolerant, non-swellable frameworks, such as activated carbon and ZIF-8. The polymer has superior function as a selective gas adsorbent, even though its constituent monomers are very simple organic feedstocks, as would be required for materials preparation on the large industrial scales required for carbon capture.

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User comments : 14

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MR166
1.9 / 5 (9) Aug 10, 2014
TheScienceEnthusiast1130
1.4 / 5 (10) Aug 10, 2014
Sigh.

Does anyone realise that carbon dioxide is safer than the alleged risk that the Israeli news media claims about carbon dioxide?
antigoracle
1.4 / 5 (10) Aug 10, 2014
Another "genius" idea from the AGW Cult, but still not as good as bio-fuels from corn though.
howhot2
4.5 / 5 (8) Aug 10, 2014
Despite the inaction that the deniers of Global Warming would force on the people world, a few brave scientists are trying to design a possible method to sequester CO2. It will take a lot because mankind produces over 26 billion tons of CO2 per year from burning fossil fuels. This would mean to capture and sequester that much gas, a lot of this CO2 absorbing material will be needed. Hurrah for the good guys.

Still if the denier have their way, and nothing is done, temperatures across the world will reach unbearable levels, extreme heat events will be normal, crop failures and total agricultural loss will devastate the food supply, and an extinction event dwarfing the Permian extinction will likely result.
Whydening Gyre
2.7 / 5 (6) Aug 10, 2014
Despite the inaction that the deniers of Global Warming would force on the people world, a few brave scientists are trying to design a possible method to sequester CO2. It will take a lot because mankind produces over 26 billion tons of CO2 per year from burning fossil fuels. This would mean to capture and sequester that much gas, a lot of this CO2 absorbing material will be needed. Hurrah for the good guys.

Just in time for Christmas...
MR166
1.7 / 5 (9) Aug 10, 2014
Nothot the problem with most of these "Breakthroughs" is that, in the long run, they actually increase the amount of CO2 emitted and the amount of fossil fuel burned.
Steve 200mph Cruiz
4.5 / 5 (8) Aug 10, 2014
Since this compound does not absorb water would we also be able to anchor pillars of these into the oceans to rebalance the PH levels around coral reefs?

Either way, well done guys, everyone wins when we fight a global problem, and this could make it a lot easier to make oil companies complicit if cheap solutions exist, although i'm sure they'll still complain, tough cookies guys.
Pexeso
1 / 5 (3) Aug 11, 2014
President Obama's plan to cut CO2 emissions 30 percent by 2030
such a solution shouldn't require a copper and another raw sources, the production of which just transfers the CO2 emissions out of fossil fuel industry, but it doesn't eliminate them. The fight against global warming shouldn't serve just as a occupational program for scientists involved and the net savings of energy should be always the main feasibility criterion here.
MR166
1.3 / 5 (6) Aug 11, 2014
".......and this could make it a lot easier to make oil companies complicit if cheap solutions exist,...."

Could you make your agenda any more clear than that?????

Fossil fuels have saved mankind from poverty and starvation. Today's "Poor" have food, housing, heat and even yesterdays extravagances such as AC that were not dreamed of pre oil and gas.

To portray the "oil" companies as villains in this new found wealth is ludicrous!
JohnGee
4.2 / 5 (5) Aug 11, 2014
The fool above me denies the existence of poverty.
Steve 200mph Cruiz
5 / 5 (3) Aug 11, 2014
MR166
Yeah, I know all about the industrial revolution. I'll also give you benefit of the doubt that you are strictly referring to the western poor.

But just because oil created the modern world, does not mean it's immortal, all technologies evolve, even energy sources. Just as the modern world could not of been brought about by burning a tree, the future world will not be able to brought about by burning a fossil. I don't share your infatuation with oil, it's just a hydrocarbon to me.

Yeah I do have an agenda, my diabolical plot is to get people to look at atomic and solar energy sources because some day with proper investment they'll be both cheaper and more efficient than oil. I have my doubts that we'll save the ice caps and polar/alpine climates, but we can at least not cross the line where the oceans acidify to the point that there's a large scale ecosystem collapse leading to a Permian style extinction, which is what would happen if we insisted on using every drop of oil.
MR166
1 / 5 (3) Aug 11, 2014
John before you cast dispersions you had better learn how fossil fuels and the companies that have provided them to us at a reasonable cost have helped increase the standard of living of the developed world.
antigoracle
1 / 5 (1) Aug 21, 2014
The fool above me denies the existence of poverty.
-- JohnGee
Pity the fool within you. I pity the fool.
Toiea
1 / 5 (1) Aug 21, 2014
The recycling of carbon dioxide could become a significant source of carbon for plastic industry in future, when we develop cold fusion or some other effective energy production method - but hardly before.
Fossil fuels have saved mankind from poverty and starvation. Today's "Poor" have food
They could pay for it in near future with wars for the rest of oil supplies. The Russian annexation of Crimea, the Middle East fights, the tension about Senkaku Islands are all motivated with nearby oil fields. Currently it's most important to develop a cheap energy source. The above process consumes the energy, it doesn't produce it.

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