‘Sponge for
CO2’ hailed in drive
for clean

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A NEW material that acts like a “sponge” to mop up greenhouse gas could help the transition to cleaner energy, according to scientists.

The brown powdery polymer is a form of plastic that holds onto large amounts of carbon dioxide when under pressure.

Carbon dioxide is already routinely removed from the chimney stacks of power plants where fossil fuels such as coal and gas are burned.

But the new material is especially suited to emerging technology that converts fossil fuels to hydrogen gas, a virtually pollution-free fuel.

Hydrogen made by the conversion process, known as integrated gasification combined cycle (IGCC), holds great promise for use in electricity-generating fuel cells.

But IGCC produces both hydrogen and carbon dioxide, which must be separated.

Lead scientist Dr Andrew Cooper, who is based at the University of Liverpool, said: “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.

“In a future landscape where fuel-cell technology is used, this adsorbent could work toward zero-emission technology.”

Adsorption differs from absorption in that the soaked up material remains in place and does not dissolve.

The polymer powder, which could be integrated into chimney stacks, expands as carbon dioxide becomes trapped in the tiny spaces between its molecules – in much the same way that a kitchen sponge swells when it gets wet.

When the pressure is lowered the “sponge” deflates and releases the gas, which can be collected for storage or conversion into useful compounds.

The material lends itself to hydrogen production from fossil fuels, since the IGCC process operates under pressure.

Tests have shown that it is highly stable, even immune to being boiled in acid, and could therefore withstand the harsh conditions in power plants.

Details of the research were presented at the annual meeting of the American Chemical Society in San Francisco.