A fast, green and one-step method for producing porous carbon spheres, which is an important component for carbon capture technology and for new ways to store renewable energy, has been developed by researchers from Swansea University.
The method produces spheres with a good ability to capture carbon, and it works effectively on a large scale.
Carbon spheres range in size from nanometers to micrometers. Over the past decade, they have begun to play an important role in areas such as energy storage and conversion, catalysis, gas adsorption and storage, medicine and enzyme delivery, and water treatment.
It is also at the heart of carbon capture technology, which traps carbon rather than pushing it into the atmosphere and tackling climate change.
The problem is that the existing methods of producing carbon spheres have disadvantages. It can be expensive or impractical, or they produce spheres that perform poorly to capture carbon. Some use biomass, which makes them more environmentally friendly, but they need a chemical to activate it.
This is where the work of the Swansea team, based in the University’s Institute for Energy Safety, is a major step forward. This paves the way for a better, cleaner and greener way to produce carbon spheres.
The team has adapted an existing method, known as CVD – chemical vapor deposition. It involves the use of heat to apply a layer to a material. Using pyromellitic acid as a carbon and oxygen source, they applied the CVD method at different temperatures, from 600-900 ° C. They then studied how efficiently the spheres capture CO2 at different pressures and temperatures
They found that:
- 800 ° C was the optimum temperature for the formation of carbon spheres
- The ultramicropores in the spheres produced gave them a high carbon capture capacity at both atmospheric and lower pressures.
- Specific surface area and total pore volume were affected by the precipitation temperature, which led to a noticeable change in the overall capacity to capture carbon dioxide.
- At atmospheric pressure the highest CO2 adsorption capacity, measured in millimolars per gram, for the best carbon spheres, was approximately 4.0 at 0 ° C and 2.9 at 25 ° C.
This new approach holds several advantages over existing methods of producing carbon spheres. It is alkali free and it does not need a catalyst to cause the sphere to form. It uses a cheap and safe raw material that is easily available in the market. No solvents are needed to purify the material. It is also a quick and safe procedure.
Dr Saeid Khodabakhshi of the Energy Safety Research Institute at Swansea University, who led the research, said:
“Carbon spheres are fast becoming vital products for a green and sustainable future. Our research shows a green and sustainable way to do that.
We have shown a safe, clean and fast way to manufacture the spheres. It is important that the micropores in our sphere perform very well to capture carbon. Unlike other CVD methods, our procedure can produce spheres on a large scale without relying on hazardous gases and liquids.
Carbon spheres are also being investigated for potential use in batteries and supercapacitors. They can therefore, over time, become essential for the storage of renewable energy, just as they already are for carbon capture. ‘
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Saeed Khodabakhshi et al. Easy and environmentally friendly synthesis of ultramicroporous carbon spheres: a significant improvement in CVD method, Carbon (2020). DOI: 10.1016 / j.carbon.2020.08.056
Provided by Swansea University
Quotation: Faster, Greener Way to Manufacture Carbon Spheres (2020, December 28) Accessed December 29, 2020 from https://phys.org/news/2020-12-faster-greener-carbon-spheres.html
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