Recycling of plastics from biodegradable bags
The end-of-life management of starch-based plastic bags is currently carried out by composting or anaerobic digestion.
This invention consists in an alternative valorization strategy of these materials in a circular economy approach.
The invention allows the end-of-life management of starch-based plastics through thermochemical processes as alternatives to composting and anaerobic digestion. This allows to recover and recycle the atoms and functionalities present in starch-based plastics by depolymerization and rearrangement, producing new chemical compounds and materials, in a circular economy perspective.
The bags containing organic waste are generally made of blends of biodegradable starch-based plastics. Usually, these materials are managed at the end of their life through composting and anaerobic digestion, which are recognized as the most effective strategy to reduce the amount of waste sent to landfill, to limit their environmental impact, and to produce energy (biogas) and / or agricultural amendments (compost or digestate). Although quaternary recycling (energy recovery) or biological approaches are among the best strategies for the treatment of starch-based plastic waste, neither primary recycling (re-extrusion of starch blends to produce similar products), nor recycling secondary (mechanical size reduction in pellets, flakes or powders), nor tertiary recycling (chemical treatment for the production of small molecules suitable as raw material for the production of new chemicals and plastics) have so far been demonstrated.
- The chemical and plastics industry, thanks to the production of chemical compounds (like dicarboxylic acids) and materials (like heterogeneous catalysts);
- The recycling of starch-based plastics, opening the possibility of a new management route (tertiary-type recycling).
- The main advantage of the invention is the possibility of “recycling” the atoms and functional groups present in the biodegradable starch-based bags, to produce new chemical compounds or plastic materials.