Gallium could play an important role in the fight against climate change in the future: Scientists in Australia have succeeded in neutralizing CO2 with the help of the technology metal.
In order to limit the consequences of man-made climate change, global emissions of greenhouse gases such as carbon dioxide (CO2) are to be significantly reduced. What is less well known is that ways are also being sought to remove CO2 that has already been produced from the atmosphere. This can then be stored or used as a raw material, for example in plastics production. One of the processes being researched is carbon capture and storage (CCS). Carbon dioxide produced in power plants, for example, is captured and stored underground.
The International Energy Agency (IEA) sees the process as an important component in achieving international climate targets. CCS could become particularly important for heavy industries such as steel or cement production, where CO2 emissions can hardly be avoided. However, the technology has also come under criticism, partly because of possible environmental hazards from escaping CO2 in the ground.
Liquid Metals Turn CO2 Into a Solid
A new research approach at Australia’s Royal Melbourne Institute of Technology could circumvent this problem: With the help of technology metals, a team of scientists succeeded in converting carbon dioxide into solid carbon flakes in a fraction of a second. This offers significant advantages in storage: As a solid, CO2 can be stored safely and in a space-saving manner, and potential problems with leaks are avoided, explains doctoral student Karma Zuraiqi in an article published by the American Society of Mechanical Engineers (ASME).
Liquid metals serve as catalysts in the conversion process, with carbon dioxide bubbling through a cylindrical column containing an alloy of mainly gallium and indium. Since gallium has a melting point of just under 30 °C, the alloy remains liquid even at low temperatures. According to the researchers involved, CO2 conversion is already possible at room temperature and without an additional reducing agent such as hydrogen. It is precisely because the new process is so simple that the team hopes it will have a real impact as a contribution to climate protection, ASME writes. Integration into existing industrial processes is possible without any problems, they say.
However, there is still a long way to go before the process is ready for the market. For example, the researchers are currently testing what percentage of the CO2 actually becomes a solid when it flows through the liquid metal. A provisional patent application has now been filed, and an initial industrial partner has been found in the form of the Australian environmental technology company ABR. Together, they now want to develop the concept into a prototype the size of a shipping container. Possible applications for the converted carbon, for example in construction materials, are also being investigated. Ideally, says co-research leader Torben Daeneke, the new method will then not only avoid CO2 emissions but also contribute to the value-added reuse of the carbon.
The study was published in Energy & Environmental Science.