Heating plastic waste in the presence of a certain chemical can produce particles that absorb carbon dioxide, according to a research team from Rice University.
The research improves on pyrolysis-based chemical recycling. Pyrolysis is the process of degrading a particular material by heating it in an inert atmosphere. When plastic is pyrolyzed, it often leaves behind oils, fumes, and waxes, as well as a waste carbon byproduct.
However, when the plastic was heated in the presence of potassium acetate, it was transformed into 0.7-1.4 nanometers particles that could hold 18% of their weight in carbon dioxide at room temperature, according to the researchers.
The new technology can facilitate development of cost-effective carbon capture methods as well as the improvement of plastic recycling.
According to the press release, current amine-based process for extracting carbon dioxide from natural gas inputs costs US$80-US$160 per tonne removed. The new material, on the other hand, may remove carbon dioxide from gas inputs for as little as US$21 per tonne.
Furthermore, the approach works on plastics that are currently resistant to chemical recycling, such as polypropylene, high-density polyethylene, and low-density polyethylene. When heated with potassium acetate, these two polymers, which make up the majority of municipal garbage, become excellent carbon absorbers.
In a press release, co-lead author James Tour explained that point sources of carbon dioxide emissions, such as power plant exhaust stacks, can be equipped with this waste-plastic-derived material to remove massive volumes of carbon dioxide that would otherwise flood the atmosphere. “It is a great way to have one problem, plastic waste, address another problem, CO2 emissions.”
The new carbon-absorbing material can also be reused. It emits carbon dioxide when heated to roughly 75 degrees Celsius, which might be used to make fuels or construction materials, while generating 90% of the material’s binding sites.