Plastic waste is a growing environmental concern. Around 60 million tonnes of plastics are produced in Europe each year , while only 30% of it is recycled. Of all the plastic waste that has been generated, 79% has ended up in a landfill or as garbage in the wild.
As Europe transitions to a more circular economy, in which materials are reused at the end of their useful life rather than discarded, improvements in plastic recycling will play an important role.
Recent measures put in place by the European Commission should help make plastic more sustainable . A strategy on plastics adopted in 2018 aims to tackle the problem by transforming the way plastic products are designed, used and recycled. A key goal is to recycle 55% of plastic packaging by 2030 . Packaging has a high environmental footprint: around 40% of the plastic produced is used for packaging, which is normally thrown away after use.
The containers are usually made of different types of plastic, which makes them difficult to recycle. Fresh foods like meat and cheese, for example, are often protected by many layers like lids, films, and trays that are not made of the same type of plastic. It is necessary to separate the different plastics before processing, as they do not mix well during conventional recycling. But doing this can be time consuming and expensive. This means that these objects are often not recycled or can be considered impossible to recycle.
“They are typically landfilled or, in the best case scenario, incinerated with energy recovery,” said Dr. Elodie Bugnicourt, innovation unit leader at IRIS Technology Solutions, an engineering company in Barcelona.
Fiber-reinforced composites often serve a similar fate. These plastic-based materials, reinforced with glass or carbon fibers, are used in a variety of interior and exterior parts of automobiles, from bumpers to textile-covered door panels. Since different materials are difficult to separate, they are normally incinerated at the end of their useful life.
A second life
However, new recycling technologies could help. As part of a project called MultiCycle, Dr. Bugnicourt and her project partners aim to extend a proprietary process, called CreaSolv and developed by the Fraunhofer Institute in Munich, Germany, that can give a second life over and over again to multilayer packaging and fiber-reinforced composites .
Using a solvent-based formula, different types of plastic and fibers are extracted and separated by dissolving them in a solution. The polymers (long chains of molecules that make up a plastic) are then recovered from solution in solid form and transformed into plastic granules. The recovered fibers can also be reused.
So far, the process shows promising benefits over existing methods. With conventional mechanical recycling, plastic tends to degrade when processed, so its use is limited. And while chemical recycling, an emerging technology that turns plastic back into small molecules or monomers, can create high-quality plastic, it can be energy intensive. With CreaSolv, the recycled plastic is of high quality and the process is more efficient. “We recover a polymer instead of a monomer, which is an advantage because we don’t need to use energy to re-polymerize the material,” said Dr. Bugnicourt.
Until now, the team has been conducting small-scale trials with multilayer and composite packaging to test the process. At the same time, it has been designing a large-scale pilot plant in Bavaria, where tests should start in July. The main challenge will be to process waste made up of complex plastic mixtures on a large scale, says Dr. Bugnicourt.
Team members have also been developing a system to monitor the composition of plastic waste. They want to be able to automatically identify the types of plastic and fiber in a product so that the process can be optimized based on the batches of materials to be recycled.
Dr. Bugnicourt believes that the system could be installed in existing recycling plants to expand the types of recycled plastics . Specialized facilities could also be created to process industrial waste. “Some packaging manufacturers that have a lot of post-industrial waste of a certain type could invest in having their own recycling plants,” he said.
Specialized
Improving existing recycling processes could also reduce the environmental impact of the types of plastic waste that are more difficult to reuse. While certain commonly used plastics are widely recycled, such as PET used to make beverage bottles, plastics with more specialized uses often are not. Technological barriers are often responsible.
“Technologies may not be mature or have the problem of not being profitable due to lack of development,” said Dr. Tatiana GarcÃa Armingol, director of the energy and environment group at the CIRCE energy research center in Zaragoza.
Dr. GarcÃa Armingol and her colleagues are demonstrating ways to increase the recovery rate of certain hard-to-recycle plastics as part of the POLYNSPIRE project. They focus on polyamides (plastics used in auto parts like gears and airbags ) and polyurethanes (flexible foam used in products like mattresses and carpets).
The team believes that conventional recycling can be improved to increase the quality of recycled plastic. To do this, they are investigating two technologies: the addition of vitrimers , a relatively new type of plastic that is both resistant and malleable, as well as the incorporation of high-energy irradiation . “Both technologies have the main objective of increasing the resistance of recycled materials and improving their properties so that they can be used in highly demanding applications”, said Dr. GarcÃa Armingol.
Other innovations they are exploring could improve chemical recycling. The technology has enormous potential to achieve a circular economy, as it allows plastic to be continuously recycled while maintaining its quality . However, its environmental footprint could be reduced. The use of microwaves or smart magnetic materials, for example, could reduce the amount of energy required to generate heat for polymerization, in which monomers produced in the recycling process join together to form the long chains of molecules that make up the plastic.
“Chemical (conventional) recycling can have a high environmental impact,” said GarcÃa Armingol. “One of our main goals is to show that it can be profitable and environmentally friendly.
Semindustrial
So far, the team has been testing the proposed technologies in the lab. They are now preparing for the engineering phase of the project where they will demonstrate that they are feasible on a semi-industrial scale. They are currently working on the pretreatment and purification stages of recycling. The next step of the project will be to demonstrate that the plastic produced with these technologies is of sufficient quality to replace the virgin material . Dr. GarcÃa Armingol and her colleagues will focus on a few applications such as automotive parts, where there are stringent quality requirements, and mattresses. Working closely with industrial partners in the automotive sector and chemical and waste management companies will also be key to the adoption of their technologies. “It is very important for us to have feedback from the industrial sector on their requirements and expectations,” said GarcÃa Armingol. “We want to show that a circular economy is possible in the plastics sector .”
ArtÃculo original.
This article was originally published in Horizon, the EU Research and Innovation Magazine
