A global collaboration has demonstrated how liquid gallium can be used to helping to achieve the important goal of net zero carbon emissions.
Engineers at the University of New South Wales (UNSW) have led research into a new cheap way to capture and convert greenhouse CO2 emissions using liquid metal.
The process can be carried out at room temperature and uses liquid gallium. to convert carbon dioxide into oxygen and a high-value solid carbon product that can then be used in batteries, or in the construction or manufacture of aircraft.
The findings have been published in the journal Advanced Materials and the team led by chemical engineering professor Kourosh Kalantar-Zadeh says the new technology has the potential to be used in a wide variety of ways to significantly reduce the levels of greenhouse gases in the atmosphere.
"We see very strong industrial applications with respect to decarbonisation. This technology offers an unprecedented process to capture and convert CO2 at an exceptionally competitive cost," he said. in a statement Junma Tang, the first author of the article.
"Applications could be in automobiles to convert polluting exhaust gases, or even on a much larger scale at industrial sites. where CO2 emissions could be captured and processed immediately using this technology.
"We have already scaled this system to two and a half litre dimensions, which can handle about 0.1 litre of CO2 per minute. And we have tested it running continuously for a whole month and the efficiency of the system does not degrade".
The newly discovered process dissolves captured CO2 gas in a solvent around gallium nanoparticles, which exist in a liquid state above 30 degrees Celsius.
The reactor also contains nano-sized solid silver rods that are the key to generating the triboelectrochemical reactions that take place once mechanical energy (e.g. stirring/mixing) is introduced.
A triboelectrochemical reaction takes place at the solid-liquid interfaces due to friction between the two surfaces, and an electric field is also created, which triggers a chemical reaction.
The reactions break the carbon dioxide into gaseous oxygen, as well as carbonaceous flakes that 'float' to the surface of the vessel due to density differences and can therefore be easily extracted.
In their paper, the research team shows a 92 percent efficiency in converting one tonne of CO2 as described, using only 230kWh of energy. They estimate that this equates to a cost of around $100 per tonne of CO2.
