Environment

Crystals of CO2 drawn from the air

Researchers Radu Custelcean (top) and Charles Seipp study crystals that had absorbed carbon dioxide from ambient air
Researchers Radu Custelcean (top) and Charles Seipp study crystals that had absorbed carbon dioxide from ambient air
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Researchers Radu Custelcean (top) and Charles Seipp study crystals that had absorbed carbon dioxide from ambient air
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Researchers Radu Custelcean (top) and Charles Seipp study crystals that had absorbed carbon dioxide from ambient air
When an aqueous solution of a simple guanidine compound was open to air, prism-like crystals started to form as the material absorbed carbon dioxide
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When an aqueous solution of a simple guanidine compound was open to air, prism-like crystals started to form as the material absorbed carbon dioxide

When we hear about carbon capture technology, it typically takes the form of sponge-like materials that are used to trap excess carbon dioxide at the places it is released, such as industrial smoke stacks. Scientists from the US Department of Energy's Oak Ridge National Laboratory, however, have created a means of drawing it right out of the ambient air – and the technology involves using a liquid to turn the CO2 gas into crystals.

The researchers started out investigating methods of removing environmental contaminants such as sulfate, chromate and phosphate from water. In order to so, they synthesized a compound known as guanidine. It binds with such pollutants, forming insoluble crystals that can subsequently be removed from the water.

However, they also discovered that when an aqueous solution of guanidine was left open to the air, it drew CO2 from that air and converted it into prism-like carbonate crystals.

When an aqueous solution of a simple guanidine compound was open to air, prism-like crystals started to form as the material absorbed carbon dioxide
When an aqueous solution of a simple guanidine compound was open to air, prism-like crystals started to form as the material absorbed carbon dioxide

In most carbon-capture scenarios, the captured CO2 needs to be converted back into a gas, so it can be piped into underground storage reservoirs. In some cases, this involves heating it as high as 900 ºC (1,652 ºF) – this obviously requires a lot of energy, potentially creating as much CO2 as has been captured. The guanidine crystals, though, only need to be heated to 80-120 ºC (176-248 ºF) – the scientists are looking into using solar energy as the heat source.

This heating turns the captured carbon back into a gas that can be piped away, and returns the guanidine to its liquid form. It can then be reused, to capture more carbon dioxide.

A paper on the research was recently published in the journal Angewandte Chemie International Edition.

Source: Oak Ridge National Laboratory

4 comments
christopher
Ignoring the fact that we need oxygen to breath, which is created by plants, which need Co2 to live. Our plants are suffocating in their own excrement, and we're doing everything we can to starve them even more? Our species are idiots.
El Bonko
Christopher, do you really think plants are suffering from too little co2 in the armor right now? Seriously?
LordInsidious
Awesome, love seeing things like this as it could help remove some of the CO2 we add to the environment.
robo
I've read scientific articles saying CO2 is currently at the low end of the range that allows plants and trees to grow and reproduce. So if we reduce CO2 even more we will end up killing earth's vegetation, and all living things would go soon after that.
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