Research into new mechanical, chemical and enzymatic recycling technologies enables us to overcome the current limitations to giving waste a second life.
At ITENE we work with innovative companies and international consortiums to develop technologies that are already revolutionising the way we recycle waste to transform it into new products. Our ultimate goal is to make the circular economy model, to which we are fully committed, a reality.
Mechanical recycling generally consists of shredding plastic waste, washing it, separating the contaminants or impurities it contains and inserting it into an extruder to obtain recycled pellets.
This process may be restricted by the presence of contaminants or multilayer structures, degradation of the materials (as a result of recycling itself), their use or their lack of homogeneity.
Various strategies based on compatibility, re-stabilisation and mixing with virgin material by extrusion are currently used to address these difficulties and improve the properties of plastic waste. Consequently, dispersion of additives in the plastic material plays a key role in achieving ideal properties.
Even so, the options are limited when it comes to highly heterogeneous, degraded and/or contaminated recycled materials, which means that their use is mainly reduced to low value-added applications.
Chemical recycling is a technology that uses chemical processes or agents to alter the chemical composition of polymers without employing energy recovery or incineration and enables us to overcome some of the limitations of mechanical recycling. It employs selective dissolution and depolymerisation processes to do so. The products obtained from these processes can be reprocessed to obtain new plastics.
Chemical recycling involves various routes and advanced recycling processes that enable the recovery of the most complex plastic waste.
Different types of products, such as decontaminated and deodorised post-consumer plastic, monomers and/or oligomers, high-value products for the chemical industry and/or other intermediate compounds, can be obtained from each of these routes.
In turn, new plastics of greater purity can be obtained from these compounds with quality levels similar to those obtained from non-renewable sources, some of which can even be used in food packaging.
Chemical recycling can overcome the limitations of mechanical recycling by enabling:
- treatment of multilayer materials.
- removal of inks from plastics.
- application that are suitable for food contact with some polymers (PP, PE or PS).
- deodorisation of recycled plastics.
- removal of dangerous contaminants.
Biotechnological recycling consists of treating non-recycled plastic fractions by the action of microorganisms, insects or enzymes. In particular, enzymatic recycling enables depolymerisation of unrecycled plastic fractions by the action of enzymes that can break down their polymeric structure.
In recent years, several enzymes capable of attacking various polymers such as PET and polyurethane have been developed, although efforts are increasingly focused on developing biological catalysts to treat other fractions such as polyamides and polyolefins.
Advantages of enzymatic recycling
- Due to the enzymes’ acute substrate specificity, this technology constitutes a powerful tool for treating complex or heterogeneous fractions, i.e., fractions that contain various problematic components, by enabling depolymerisation of a particular polymer without the need to perform complex pre-treatment in order to be able to classify them.
Enzymatic or biotechnological recycling enables us to overcome the limitations of mechanical and chemical recycling by enabling the following processes:
- treatment of multilayer materials.
- treatment of polymers present in mixed or rejected fractions
- treatment of microplastics
2. Low energy consumption is another advantage of this type of process, since it takes place in mild temperature and pH conditions (within the biological range). Finally, the process always takes place in water-based media which means that its environmental impact is negligible.
- Consequently, biotechnology also enables us to obtain high value-added products from plastic waste, including polymers with properties similar to virgin polymers.
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Recycling Technologies and Waste Management Area Manager