New material captures CO2 from air and stores in ocean as baking soda

Carbon capture technology has been around for years. But they primarily focused on capturing CO2 from pollution sites such as coal and steel plants' chimneys before it entered the atmosphere. On a larger scale, we'll need complicated machines and sophisticated tech but the road ahead is riddled with challenges.

However, Lehigh University, Pennsylvania researchers have identified a material that could be a game-changer in the direct air capture (DAC) industry.

Arup SenGupta at Lehigh University and his colleagues developed a new absorbent material called a sorbent that can pull more CO2 from the air than existing materials. According to the researchers, modifying amine solvents with a copper solution increased the carbon capture potential of DAC by two to three times.

"Amine means they have nitrogen atoms," Sengupta told Gizmodo. "Nitrogen and copper, they love each other."

The new material could prove DAC as an affordable and effective technology to mitigate climate change.

"This material can be produced at very high capacity very rapidly," SenGupta told NewScientist. "That definitely should improve the cost-effectiveness of the process."

Dawid Hanak at Cranfield University in the UK said the research could "substantially reduce the cost of DAC".

The proposal is "elegant and clever chemistry"

Now comes the exciting part. This captured CO2 can be converted into sodium bicarbonate, or baking soda, thanks to seawater. The team said this will then be stored in the ocean, as it is an "infinite sink" for captured carbon.

As sodium bicarbonate is an alkali, it could reverse the acidification of the ocean that naturally takes place and pose no ecological harm. "Higher alkalinity also means more biological activity; that means more CO2 sequestration," said SenGupta. He said DAC plants utilizing the sorbent could eventually be installed offshore.

The proposal is “elegant and clever chemistry. [The] ability to store directly into seawater is also powerful because the very deep ocean has an immense capacity for accessible CO2 storage lasting hundreds to thousands of years," Stuart Haszeldine at the University of Edinburgh, UK, said.

However, more research must be done to clearly understand how the material performs on a larger and industrial scale after absorbing and releasing CO2 hundreds of times.

"I’ve argued consistently that the only way this will ever happen at the scale it needs to happen is if it’s made a licensing condition of continuing to sell fossil fuels,” Myles Allen at the University of Oxford told NewScientist. "As soon as it is, it will happen on a scale that’s currently unimaginable."

The study is published in Science Advances.

Study Abstract:

Direct air capture (DAC) is important for achieving net-zero greenhouse gas emissions by 2050. However, the ultradilute atmospheric CO2 concentration (~400 parts per million) poses a formidable hurdle for high CO2 capture capacities using sorption-desorption processes. Here, we present a Lewis acid-base interaction–derived hybrid sorbent with polyamine-Cu(II) complex enabling over 5.0 mol of CO2 capture/kg sorbent, nearly two to three times greater capacity than most of the DAC sorbents reported to date. The hybrid sorbent, such as other amine-based sorbents, is amenable to thermal desorption at less than 90°C. In addition, seawater was validated as a viable regenerant, and the desorbed CO2 is simultaneously sequestered as innocuous, chemically stable alkalinity (NaHCO3). The dual-mode regeneration offers unique flexibility and facilitates using oceans as decarbonizing sinks to widen DAC application opportunities.