A team of scientists believe they have made a "significant advance" capturing carbon dioxide with a little bit of help from one of the main ingredients in baking soda.
They developed microcapsules made up of "a highly permeable polymer shell" and a fluid composed of sodium carbonate solution* to suck out carbon dioxide from coal or natural gas-fired power plants.
The method involving the first demo of its kind for controlled CO2 capture and release can also apparently be used in industrial processes such as steel and cement production.
Boffins at the Lawrence Livermore National Laboratory worked alongside researchers from the University of Illinois and Harvard University to develop a carbon capture media containing core-shell microcapsules.
The lab said:
The aim of carbon capture is to prevent the release of large quantities of CO2 – a greenhouse gas that traps heat and makes the planet warmer – into the atmosphere from fossil fuel use in power generation and other industries.
However, currently used methods, while successful, can be harmful to the environment. The ability to move away from caustic fluids, such as monoethanol amine to capture CO2, to more environmentally benign ones, like carbonates, is a key attribute of the team’s research.
Using sodium carbonate as the active chemical was a key development, said Lawrence Livermore researcher Roger Aines.
“Corrosiveness also is improved because the chemical is more benign and always is encapsulated," he said.
"Putting the carbonate solution inside of the capsules allows it to be used for CO2 capture without making direct contact with the surface of equipment in the power plant, as well as being able to move it between absorption and release towers easily, even when it absorbs so much CO2 that it solidifies."
The team's encapsulation process work was backed by US government funding from the Advance Research Projects Agency-Energy (ARPA-E).
Aines added that sodium carbonate would never degrade in the way that the current technology, amines, does. “It can be reused forever, while amines break down in a period of months to years,” he said.
“Capturing the world’s carbon emissions is a huge task. We need technology that can be applied to many kinds of carbon dioxide sources with the public’s full confidence in its safety and sustainability.”
The research paper – Encapsulated liquid sorbents for carbon dioxide capture – was published in the Nature Communications journal on 5 February. ®
Top image credit: Lawrence Livermore National Lab
* How to make baking soda (NaHCO3, sodium bicarbonate) from soda ash (Na2CO3/ sodium carbonate ): bung it in a centrifuge to separate liquid from crystals. Dissolve crystals in a bicarbonate solution. Filter to remove non-soluble stuff, pump to the top of a carbonating tower. Add purified carbon dioxide into the bottom of the tower (under pressure). Saturated sodium solution moves through tower, cools and reacts with the carbon dioxide to form sodium bicarbonate crystals. Wash crystals in a bicarb solution to form a cake. Dry the cake out to create powdered NaHCO3.