‘Wonder material’ scrubs CO2 from power plants before it reaches the atmosphere

Scientists have discovered a reusable material that can capture carbon dioxide from coal-fired power plants and prevent the greenhouse gas from entering the atmosphere.

A team from the National Institute of Standards and Technology (NIST) in the US claim that the aluminium formate material, known as ALF, lacks the shortcomings of other proposed carbon filtration methods and is made of substances found abundantly.

“What makes this work exciting is that ALF performs really well relative to other high-performing CO₂ adsorbents, but it rivals designer compounds in its simplicity, overall stability and ease of preparation,” said Hayden Evans, a chemist at the NIST Center for Neutron Research (NCNR).

“It is made of two substances found easily and abundantly, so creating enough ALF to use widely should be possible at very low cost.”

Coal-fired power plants account for around 30 per cent of all CO₂ emissions globally, with estimates from the International Energy Agency (IEA) finding that coal combustion was responsible for over 0.3°C of the 1°C increase in global average annual surface temperatures above pre-industrial levels.

This makes it the single largest source of global temperature increase, and many countries continue to rely on it to meet growing energy demands despite the transition to renewable energy sources like wind and solar.

The use of the ALF material to scrub the CO₂ from the flue gas could significantly reduce the environmental impact of these power plants while they remain in operation.

Until now, scrubbing the CO₂ directly from the smokestacks has proved tricky as the gases flowing up the chimneys are hot, humid and corrosive. Materials that work have typically been too expensive to be economically viable, while less expensive options only work in certain conditions.

“Put it all together, you need some kind of wonder material,” Dr Evans said. “Here, we’ve managed to tick every box except stability in very humid conditions. However, using ALF would be inexpensive enough that a drying step becomes a viable option.”

The NIST researchers claim that the CO₂ captured from the exhaust streams could also be converted to formic acid, which could then be used to create more ALF.

“There is a great deal of research going on nowadays into the problem of what to do with all the captured CO₂,” Dr Evans said.

“It seems possible that we could eventually use solar energy to split hydrogen from water, and then combine that hydrogen with the CO₂ to make more formic acid. Combined with ALF, that’s a solution that would help the planet.”

A paper detailing the material, titled ‘Aluminum formate, Al(HCOO)₃: An earth-abundant, scalable, and highly selective material for CO₂ capture’, was published in the scientific journal Science Advances on Wednesday.