Sponge-like plastic to soak up CO2, reduce pollution

Scientists have developed a sponge-like plastic that sops up carbon dioxide (CO2) and might ease our transition away from polluting fossil fuels and towards new energy sources, such as hydrogen.
The material - a relative of the plastics used in food containers - could play a role in cutting CO2 emissions, and could also be integrated into power plant smokestacks in the future.
"The key point is that this polymer is stable, it's cheap, and it adsorbs CO2 extremely well. It's geared towards function in a real-world environment," said Andrew Cooper from the University of Liverpool in UK.
"In a future landscape where fuel-cell technology is used, this adsorbent could work toward zero-emission technology," said Cooper.

CO2 adsorbents are most commonly used to remove the greenhouse 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 fossil fuels 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 hydrogen and CO2 gas, which must be separated.

Cooper 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.