Technologies for sorting and recycling of multilayer plastics residues (Public Summary)

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 101036838. D3.14 – Technologies for sorting and recycling of multilayer plastics residues January 2025 Authors: Salvador Navarro (GWC); Mari Carmen Cánovas (GWC) Ref. Ares(2025)6385308 - 05/08/2025 A2C – Deliverable D3.14 v1.0 Page 2 І25 Technical references Project Acronym Agro2Circular Project Title TERRITORIAL CIRCULAR SYSTEMIC SOLUTION FOR THE UPCYCLING OF RESIDUES FROM THE AGRIFOOD SECTOR Project Coordinator Fuensanta Monzó CETEC [email protected] Project Duration October 2021 – March 2025 (42 months) Deliverable No. D3.14 Dissemination level* PU Work Package WP 3 – A2C technologies for the sorting and recycling of multilayer plastics residues Task Task 3.1 Plastic waste pre-treatments and preliminary decontamination. Task 3.2 Optical sorting of the multilayer materials. Task 3.3 Physical recycling of complex multilayers containing aluminium. Task 3.4 Enzymatic recycling of multilayer structures based on PE/PET Task 3.5 Mechanical recycling of simple multilayer structures and products from physical recycling Lead beneficiary Green World Compounding (GWC) Contributing beneficiary/ies GWC, SAPERATEC, IRIS, BOKU, WETSUS, CEW and EPOCH Due date of deliverable 30 September 2024 Actual submission date 28 January 2025 * PU = Public PP = Restricted to other programme participants (including the Commission Services) RE = Restricted to a group specified by the consortium (including the Commission Services) A2C – Deliverable D3.14 v1.0 Page 3 І25 CO = Confidential, only for members of the consortium (including the Commission Services) Document history V Date Comments v0.1 10/12/2024 First draft of document v0.2 11/12/2024 Revised version based on the comments of Alexandra Poch (IRIS) and Dennis Meisel (SAPERATEC) V0.3 18/12/2024 Revised version based on the comments of Charlotte Gruender (EPOCH) and Janneke Dickhout (CEW) V0.4 10/01/2025 Revised version based on the comments of Ronald Zirbs (BOKU) v1.0 28/01/2025 First final version, approved by the WP leader and the project coordinator, (will be) submitted to EC Document Distribution Log Version Date Distributed to v0.1 10/12/2024 First draft of document distributed to the contributing beneficiaries V0.2 17/12/2024 Revised version based on the comments of Alexandra Poch (IRIS) and Dennis Meisel (SAPERATEC) distributed to Charlotte Gruender (EPOCH) and Janneke Dickhout (CEW) V0.3 14/01/2025 Revised version based on the comments of Ronald Zirbs (BOKU) distributed to the WP leader and the project coordinator Verification and approval Name Date Verification Final Draft by WP leader Salvador Navarro Navarro 28/01/2025 Approval Final Deliverable by coordinator Fuensanta Monzó 28/01/2025 A2C – Deliverable D3.14 v1.0 Page 4 І25 Disclaimer and acknowledgement This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101036838 Disclaimer This document reflects only the views of the author(s) the European Research Executive Agency (REA) is not responsible for any use that may be made of the information it contains. Whilst efforts have been made to ensure the accuracy and completeness of this document, the A2C consortium shall not be liable for any errors or omissions, however caused. A2C – Deliverable D3.14 v1.0 Page 5 І25 Table of contents List of abbreviations .......................................................................... 6 1 Executive summary <abstract> ................................................... 7 2 Introduction .................................................................................. 9 3 KEY ADVANCEMENTS IN THE RECYCLING OF COMPLEX MATERIALS ................................................................................... 10 3.1 ADVANCES IN PLASTIC WASTE CONDITIONING .......................................... 10 3.2. ADVANCEMENTS IN THE DECONTAMINATION OF RECYCLED PLASTIC .. 12 3.3. ADVANCEMENTS IN OPTICAL SORTING PROCESS ..................................... 15 3.4. ADVANCEMENTS IN PLASTIC FRACTION DELAMINATION .......................... 16 3.5. PLASTIC PROCESSABLE COMPOUNDS ........................................................ 17 3.6. ADVANCES IN ENZYMATIC TREATMENT ....................................................... 19 3.7. ADVANCES IN ALUMINIUM MODIFICATION ................................................... 20 3.8. ORGANIC BY-PRODUCTS RECOVERY AND MICROPLASTIC REMOVAL .... 22 4 Conclusions ............................................................................... 25 A2C – Deliverable D3.14 v1.0 Page 6 І25 List of abbreviations GWC: Green World Compounding CETEC: Technological Center for Footwear and Plastics PE: Polyethylene PP: Polypropylene DPP: Digital Product Passport PHA: Polyhydroxyalkanoates WP6: Work Package 6 A2C Agro2Circular EG Ethylene Glycol PIB Polyisobutylene NIAS Non-Intentionally Added Substances NIR-HIS Near Infrared – Hyperspectral Imaging PET Polyethylene Terephthalate LDPE Low-Density Polyethylene PA Polyamide EVOH Ethylene Vinyl Alcohol DSC Differential Scanning Calorimetry FT-IR Fourier-Transform Infrared Spectroscopy TGA Thermogravimetric Analysis HDPE High-Density Polyethylene H2O2 Hydrogen Peroxide CO2 Carbon Dioxide LIBS Laser-Induced Breakdown Spectroscopy FAT Factory Acetoce Text APTES (3-aminopropyl)ethoxysilane A2C – Deliverable D3.14 v1.0 Page 7 І25 1 Executive summary <abstract> The plastic waste generated in the agri-food and agricultural sectors presents significant technical challenges. Its multi-layered nature combines different plastic materials and is often contaminated with agrochemicals and organic waste. These factors make the application of conventional recycling methods difficult. Due to their complex composition, these plastic wastes require advanced technologies that allow for efficient separation and proper decontamination. This process ensures the removal of contaminations such as agrochemicals, soil, and organic matter, enabling the effective reuse of the materials. In this context, various treatment technologies in line have been researched and developed to recover and transform the plastic waste fractions into valuable raw materials. The goal is to obtain high-value-added recycled products, such as non-aluminized plastic fractions, modified aluminium, alkanes, EG (ethylene glycol), TPA (terephthalic acid), and organic byproducts. These materials will be used to create new compatibilized synthetic polymers, biodegradable polymers, as well as to develop end products for cosmetic applications and other industries, through the demonstration of the A2C Technological Solution, which will be carried out in Work Package 6. To achieve this goal, a line for shredding, cleaning, and drying plastic materials has been developed, allowing the production of a small size clean fraction ready to be classified. This process includes an optical sorting stage that distinguishes between fractions containing aluminium and those that do not. The fractions are then processed differently: 1. Fraction with aluminium: This fraction undergoes a delamination process to separate the aluminium from plastics. Then, an enzymatic modification is performed on the plastics present to obtain their monomers, optimizing their upcycling and enabling valorisation. Furthermore, the aluminium removed from the plastic fractions is modified to improve the compatibility with the plastic matrix and therefore, improved properties in films for specific applications. A2C – Deliverable D3.14 v1.0 Page 8 І25 2. Fraction without aluminium: This fraction is subjected to a compatibilization process, where compatibilizers are added to improve the mix between the different types of polymers. This allows for the production of compatibilized synthetic plastics that are recycled and recyclable, with enhanced properties that can be used in various industrial applications, from packaging to everyday plastic products. This innovative solution will significantly contribute to the reduction of plastic waste while promoting the recovery of valuable materials and improving sustainability in industrial processes. In addition to this, it is worth highlighting that an example of this is the organic by-products recovery and microplastic removal, where organic matter recovered from wastewater treatment could potentially be used to obtain PHA (Polyhydroxyalkanoates). However, the concentration of organic matter at this point may not yet be high enough, as it depends on the plastics and particularly on how ‘fresh’ the organic matter is. This is an area that we hope to explore further in WP6. A2C – Deliverable D3.14 v1.0 Page 9 І25 2 Introduction Plastic recycling remains one of the most significant challenges in the search for sustainable solutions for waste management. In particular, multi-layer aseptic bags used as packaging in the liquid food industry and agricultural disinfection films, which are materials made up of several layers of different polymers and, in some cases, metals like aluminium. These combinations make recycling extremely complex, as the materials must be properly separated before they can be reused. Within the framework of the Agro2Circular project, innovative separation technologies have been developed and tested for these multi-layer plastics. This report provides a detailed description of the most relevant advancements achieved in the various phases of the project, including innovative technologies for material separation, the improvement of recycled plastic properties, and biological processes that allow the transformation of certain polymers into valuable components for the production of other relevant products in the industry. A2C – Deliverable D3.14 v1.0 Page 16 І25 metallised fractions within plastic aseptic bags were studied during the first part of the project (NIR-HSI, Laser induced breakdown spectroscopy -LIBSand the use of a metal detector). After the observation of the results and after analysing the samples through the mentioned techniques, the most promising technique that would showcase technical feasibility in an industrial environment is NIR-HSI. Some challenges with overlapping and sorting typical of light, flexible and small size samples have been tackled in the last months. As well, the size of the grinding required for the implementation of the sorting device was optimized and some feeding speed tests were carried out. At this stage, the specifications of the optical sorting prototype have been established, the design of the equipment has been carried out and the prototype is being developed, including the mechanical, electric, electronical, software, automation and optical systems. The next steps will be to carry out the Factory Acceptance Tests (FAT), which will be performed to guarantee that the components are running properly and the monitoring and sorting systems have a good performance in an industrial environment. Finally, a pilot scaleup will be taking place in order to evaluate the performance of the prototype in a real environment (at GWC facilities), coupling the monitoring and sorting unit with other processes. This work will be done in the framework of task 6.1 “Integration of the technologies at pilot scale”. 3.4. ADVANCEMENTS IN PLASTIC FRACTION DELAMINATION The aluminized fractions described in this section, obtained through optical sorting, originate from complex structures widely used in the packaging industry, such as barrier-laminates with aluminium-metallization or aluminium sheets. These materials present unique recycling challenges due to the need for effective separation of their components to maximize the purity of recovered materials and ensure their efficient reuse. Saperatec's technology leverages specially designed separation fluids that enable the delamination of these composites, separating aluminium and polymers. Below are the achievements and limitations identified so far. A2C – Deliverable D3.14 v1.0 Page 17 І25 Results Achieved: • Laminates with aluminium-metallization and aluminium sheets were successfully delaminated, separating PE, PET, and aluminium fractions effectively. • In the case of laminates with aluminium sheets, aluminium was recovered alongside plastics, improving recycling efficiency and reducing CO2 footprint. • The separation fluid proved reusable across multiple delamination cycles without loss of efficacy. • The delamination and separation process was validated at a pilot scale, achieving good results in sorting materials with significant density differences (e.g., PE and PET). • Recovered materials, including PE, PET and aluminium, retained high quality and purity after treatment with the separation fluid. Limitations and Next Steps: • Separating materials with close densities (e.g., PE and PET/PE) requires further development and optimization. • The existing pilot equipment cannot be transported due to its size and complexity, necessitating the design of a demonstrator tailored to the project's requirements. 3.5. PLASTIC PROCESSABLE COMPOUNDS The development of processable compounds using recycled plastics derived from aseptic bags and multilayer agricultural films has been successfully carried out. To validate the procedure, polymer blends such as LDPE, PA, and EVOH were mixed with compatibilizers in various concentrations. These blends were subsequently subjected to A2C – Deliverable D3.14 v1.0 Page 18 І25 detailed evaluations to analyse their performance and compatibility. The process included key stages such as extrusion, calendering, and thermal, mechanical, and structural characterization of the blends. The results demonstrated significant advancements in optimizing compatibilizers and improving the final properties of recycled materials. However, challenges remain in achieving complete integration of the polymers, which must be addressed in pilot-scale industrial tests. A significant milestone was the successful production of 40-micron films via calendering, using compatibilizers in industrially realistic proportions (3% to 5%). Additionally, the characterization of the blends, carried out through techniques such as DSC, FT-IR, and TGA, provided crucial data on the thermal stability and compatibility of the developed materials. Results Achieved: • Improved Compatibility: Partial compatibility was achieved between immiscible polymers through the use of compatibilizers, enhancing mechanical properties in some blends. • Interaction Mechanisms Identified: Key mechanisms of interaction between compatibilizers and polymers were identified, though conclusive evidence was lacking in some cases. Limitations and Next Steps: • Persistent Immiscibility: LDPE, PA, and EVOH showed immiscibility even with compatibilizers in certain samples. • Reduced Elongation: Significant reductions in elongation at break were observed in samples containing compatibilizers. • Thermal and Mechanical Variability: High variability in thermal and mechanical properties depending on specific compositions. • Industrial Scale Testing Required: These advancements still need to be tested at an industrial scale to evaluate their commercial viability. A2C – Deliverable D3.14 v1.0 Page 19 І25 3.6. ADVANCES IN ENZYMATIC TREATMENT This section addresses the advancements in enzymatic recycling of PE/PET plastic sheets (non-aluminized) obtained through delamination (Section 3.4). It focuses on enzyme engineering (PETase and PEase) to break down these plastics into their base monomers, facilitating their valorization and preventing their usual disposal in landfills. Results Achieved: o PETase: A sixfold increase in enzymatic activity was achieved using directed evolution methods, advanced computational design, and machine learning. A protocol was also developed for the recovery of products such as TPA and EG, scaling reactions to 100 g. o PEase: The initial enzyme was not viable for industrial use, leading to the design of a de novo enzyme. Although a stable and promising design was achieved, the required activity levels for PE have not yet been reached. o The improved PETase activity was evaluated on pretreated PET samples and PE/PET bilaminates. It was concluded that bilaminate layers are unsuitable for this type of enzymatic recycling. o The enzymatic depolymerization reaction was scaled up to a 1 L reactor, achieving high-purity product recovery through ultrafiltration. Limitations and Next Steps: o Integrating PEase at an industrial level remains a challenge due to low activity in the initial variants. A2C – Deliverable D3.14 v1.0 Page 20 І25 o The incompatibility of PE/PET bilaminates with enzymatic depolymerization. o The thermal stability of the improved PETase still requires optimization for commercialization. 3.7. ADVANCES IN ALUMINiUM MODIFICATION The described process aims to enhance compatibility between aluminium particles (obtained through the delamination process) and polymer matrices, particularly in hydrophobic polymers such as HDPE and PP. The main challenge lies in the fact that aluminium particles are typically hydrophilic due to the passivated oxide layer on their surface, while the polymers into which they are incorporated are hydrophobic. This disparity causes dispersion issues, negatively affecting the mechanical, optical, and barrier properties of the materials. To address this problem, the proposed process modifies aluminium particles with a polyisobutylene (PIB) shell, improving their compatibility and dispersion within the polymer matrix. The key stages of this process are outlined below. o Obtaining Aluminium Particles: Aluminium particles are recovered from multilayer materials with aluminium barriers. These particles are obtained through a separation technology developed by the partner Saperatec, which produces pure aluminium particles in both nanometric and micrometric sizes. o Treatment of Aluminium Particles: Aluminium surfaces oxidize in air, forming a passivated layer containing -OH groups. To increase the quantity of these groups, the aluminium particles are treated with hydrogen peroxide (H₂O₂) at high temperatures, facilitating the formation of chemical bonds with suitable groups (e.g., acid, silane, or phosphate) in subsequent stages. o Controlled Synthesis of Polyisobutylene (PIB): PIB is synthesized via controlled cationic polymerization to produce a polymer with a specific molecular weight and A2C – Deliverable D3.14 v1.0 Page 21 І25 low polydispersity. The process utilizes appropriate initiators (such as TMPCl) and reaction conditions to achieve high-quality PIB. o Modification of PIB Chain Ends: During the PIB synthesis process, the polymer’s chain end is modified through a Friedel-Crafts alkylation reaction using compounds like (3-aminopropyl)ethoxysilane (APTES). This introduces reactive groups into PIB, enabling its binding to the surface of aluminium particles. o Grafting of PIB onto Aluminium Particles: Pre-treated aluminium particles are chemically modified with functionalized PIB (via APTES) through a grafting reaction, forming covalent bonds between PIB and the aluminium surface. This step ensures that the aluminium particles are coated with a PIB shell, enhancing their dispersion in the polymer matrix. o Evaluation of Dispersion and Material Properties: PIB-modified aluminium particles are dispersed in polymers such as HDPE or PP. The resulting composite materials are evaluated for mechanical, optical, and barrier properties, aiming for significant improvements compared to materials containing unmodified aluminium particles. Results Achieved: • Successfully modified aluminium particles with a polyisobutylene (PIB) shell, improving their dispersibility in organic solvents and hydrophobic polymers like HDPE or PP, enhancing their compatibility with polymer matrices. • Surface modification of aluminium through H₂O₂ treatment, followed by PIB modification using APTES, rendered the treated aluminium particles hydrophobic, improving their dispersion in polymeric materials. A2C – Deliverable D3.14 v1.0 Page 22 І25 • Achieved controlled PIB synthesis with a low polydispersity index using TMPCl as an initiator, creating PIB with appropriate molecular weight for modifying aluminium particles. • The composites produced were optically homogeneous and the mechanical properties did not change in direct comparison to PP materials without fillers. • A process has been developed in which commercially available PIB can also be used directly for the successful modification of aluminium particles (e.g. KOMAD ADDITIVE). This makes successful realization - even on a large scale - possible and probable. • The developed method can be transferred directly to other (nano-)particle systems, e.g. aluminium oxide, clay and various oxides. Limitations and Next Steps: • Size of aluminium particles need to be more homogenous and better controlled (smaller particles) • Variation of PIB (synthesis or commercially) not easy to achieve • Optimization of barrier properties is low in comparison to eg aluminium-films 3.8. ORGANIC BY-PRODUCTS RECOVERY AND MICROPLASTIC REMOVAL This section focuses on evaluating and developing technologies for treating wastewater generated during the washing of plastics in the pre-treatment phase. Two main technologies were investigated: ultrafiltration membrane filtration and electrocoagulation. The objectives were to remove contaminants such as microplastics and organic matter from the A2C – Deliverable D3.14 v1.0 Page 23 І25 wastewater while exploring the reuse of the organic fraction for the production of bioplastics (PHA). Additionally, a pilot system was designed to test these technologies under conditions closer to real-world operations. The trials included chemical analyses of the wash water, evaluation of contaminant removal efficiency, and the feasibility of implementing these processes in a closed-loop system. Results Achieved: • Both technologies effectively removed microplastics, significantly reducing potential contamination before the water could be discharged or reused. • Part of the dissolved organic matter in the water was successfully recovered, with potential reuse as a raw material for bioplastic (PHA) production, promoting process sustainability. • A pilot system was designed and adapted to assess the performance of these technologies under conditions resembling industrial environments. • Electrocoagulation proved particularly effective at removing turbidity and water color, as well as separating the organic fraction into distinct layers (upper or lower), facilitating handling. • Pilot-scale ultrafiltration tests confirmed that with appropriate flow rates, permeate rates could be increased without significantly compromising process efficiency. • The tested technologies demonstrated their potential to advance toward closed-loop systems, minimizing water waste and reducing environmental contamination. Limitations and Next Steps: • A tendency for membranes to foul requires regular cleaning, which could increase operational costs. • Current electrocoagulation equipment does not allow for adequate collection of separated solids, limiting their recovery potential. Moreover, it adds either iron or aluminium hydroxides to the water, which might be limiting the reuse potential for A2C – Deliverable D3.14 v1.0 Page 24 І25 PHA production as they might be toxic. Additionally, both technologies remove the pollutants from the water, but they are collected in a waste stream. In WP6, an strategy for the valorization of the by-product, including water reuse, will be studied. A2C – Deliverable D3.14 v1.0 Page 25 І25 4 . Conclusions The Agro2Circular project has made significant progress in overcoming the technical challenges of recycling agro-food and agricultural plastics, which have a multi-layer structure and are contaminated with agrochemicals and organic waste. The developed technologies, such as washing, optical sorting, delamination of aluminium fractions, and enzymatic modification of plastics, have proven highly effective in separating and decontaminating these complex materials. These processes have enabled the recovery of high-value-added recycled plastics, such as non-aluminized plastic fractions and modified aluminium. In the latter case, an innovative method has been developed to modify (nano)particles of (oxide) aluminium with a hydrophobic shell, improving their compatibility with hydrophobic polymers to obtain composites with improved properties. Additionally, organic products derived from wastewater treatment have been successfully recovered. Now, in Work Package 6 (WP6), the next crucial step will be to scale these advances from the laboratory to a pilot scale. In this new phase, an online pilot-scale demonstrator will be implemented, allowing the validation and evaluation of the developed processes and technologies under real-world conditions. This demonstrator will focus on optimizing the efficiency and industrial feasibility of the technological solutions, enabling the assessment of their performance, scalability, and commercial viability in a large-scale production environment.