Environmentally Friendly Method for Recycling Plastic Waste

Unmet Need: Easy recycling of difficult to discard plastics

Extensive use of plastics has led to waste disposal management difficulties and serious environmental problems such as intensive energy consumption, toxic gas emission, and occupying many landfills as synthetic plastics such as polyethylene terephthalate (PET) do not rust and are not easily degraded in an outdoor environment. Therefore, there is a need to provide a high-efficiency, low-energy consumption, and environmentally friendly recycling technology for PET plastic waste.  PET plastic accounts for ~8% of the total waste plastics.

The Technology: Environmentally friendly reactor for the recycling of plastics

The inventors have developed a reactor and a method thereof that demonstrates a possible use of multifunctional CO2 to depolymerize PET waste plastic. This technology requires a low energy consumption and is performed under mild operation conditions. Degradation of PET plastic can be difficult due to the necessary harsh reaction conditions. The crystalline melting temperature for PET plastic is 260 and it shows superior chemical, hydrolytic and organic solvent resistance. The new technology utilizes low temperatures, does not require organic solvents, and reaches 100% depolymerization in under 2 hours.


  • Recycling waste plastic
  • Synthesis of desirable monomers
  • High pressure chemistry
  • Organic chemistry


  • Water and CO2 are the only reagents
  • Plastic monomers and CO2 are recycled
  • Relatively low temperatures

Patent Information:

Utility patent application has been filed.

Learn More

Punam Dalai
Technology Licensing Associate
Washington State University
Reference No: TECH-21/3422


Jinwen Zhang

Key Words

Carbon Dioxide
chemical recycling
Human Impacts and environmental change
Waste plastics