How Dissolution Technology is Overcoming the Limits of Traditional Recycling, Improving Sustainability and Efficiency

by Marco Arezio

The modern era has seen exponential growth in the use of polymers, versatile materials used in a wide range of applications, from simple household tools to advanced components in high-tech industries. However, the durability that makes polymers so valuable is also the cause of one of the most pressing environmental problems: the accumulation of plastic waste.

Recycling emerges as a critical solution, but traditional methods, mechanical and chemical, have significant limitations in terms of efficiency, costs and environmental impact. In this context, physical recycling is proposed as an innovative recycling methodology, promising to address these challenges through a dissolution process that separates polymers from contaminants, pigments and additives, without degrading the material or requiring intensive use of energy. .

Polymer Recycling

Description of Polymers

Polymers are macromolecules composed of repeating units, known as monomers, linked together by covalent bonds. This structure gives them unique properties of strength, flexibility and durability, making them ideal for a myriad of industrial and everyday applications.

However, these same characteristics make polymers particularly resistant to natural degradation, contributing to the global problem of plastic pollution.

Environmental impact

The environmental impact of polymer waste is vast and multidimensional. Accumulating in landfills and natural environments, polymers not only take up physical space but also release toxic substances during slow degradation, contaminating soil and water.

Furthermore, the degradation of polymers in marine environments contributes to the formation of microplastics, very small particles that can be ingested by marine fauna, thus entering the food chain.

Traditional Recycling Methods

Mechanical recycling involves physical processes such as shredding and remelting plastic waste to create new objects. Although economically advantageous, this method tends to degrade the quality of the polymers, limiting their reuse to lower quality products.

Chemical recycling, on the other hand, chemically breaks down polymers into monomers or other usable chemicals. This process theoretically allows plastic to be recycled infinitely. However, it is more expensive, requires high energy consumption and often involves the use of dangerous chemicals.

Both methods therefore present significant limitations in terms of environmental sustainability, energy efficiency and material recovery capacity. These considerations lay the foundation for the exploration of alternative recycling methodologies, such as physical recycling.

Principles of Physical Recycling

Physical recycling represents an innovative approach in the panorama of polymer recycling. It differs from mechanical and chemical methods in its ability to separate polymers from various additives and contaminants without altering their chemical structure. This process is based on two fundamental principles:

Concept of Dissolution and Separation

The heart of physical recycling lies in the selective dissolution of polymers in specific solvents. These solvents are chosen for their ability to interact with the target polymer without affecting additives, pigments or contaminants.

Once the polymer is dissolved, the solution can be filtered to remove impurities. Subsequently, the polymer can be precipitated from solution through variation in temperature, pressure, or addition of a non-solvent, thus allowing recovery of the pure polymer.

Advantages compared to Traditional Methods

The main advantage of physical recycling is its ability to recover high-quality polymers without degrading their mechanical properties.

Unlike mechanical recycling, which tends to compromise the quality of the recycled material, physical recycling maintains the molecular integrity of the polymers.

Compared to chemical recycling, it stands out for its lower energy consumption and the absence of complex breakdown and synthesis processes, making it more sustainable and economically advantageous.

Physical Recycling Technology and Process

The physical recycling process is divided into different phases, each of which plays a crucial role in the recovery of polymers:

Sorting and Pretreatment: Plastic waste is sorted and cleaned to remove gross impurities.

Dissolution: The plastic material is immersed in a specific solvent which dissolves the polymer, leaving behind additives and contaminants.

Filtration: The solution is filtered to separate the dissolved polymer from the solid impurities.

Precipitation and Recovery: The polymer is recovered from solution by precipitation, caused by changes in temperature, pressure, or the addition of a non-solvent.

Purification and Drying: The precipitated polymer is further purified and dried to remove any traces of solvent, making it ready to be reused in the production of new items.

This technology not only allows the recovery of high quality polymers but also introduces a more sustainable and energy efficient recycling cycle.

Environmental and Economic Benefits of Physical Recycling

Physical recycling offers numerous environmental and economic benefits. By reducing energy consumption and minimizing waste production, it significantly contributes to reducing the ecological footprint of the polymer industry.

Furthermore, the recovery of high-quality polymers can reduce dependence on fossil resources, lowering production costs and encouraging the adoption of more sustainable practices.

Physical recycling, distinguishing itself from traditional recycling methods by its ability to maintain the properties of the polymers unaltered and by its lower environmental impact, offers significant advantages from both an environmental and economic point of view.

Reduction of Environmental Impact

Lower Energy Consumption: The process of dissolving and separating polymers requires less energy than the chemical breakdown of polymers into monomers or the heating and melting process in mechanical recycling.

Waste Reduction: The ability to recover and reuse polymers with high efficiency reduces the amount of plastic waste sent to landfills or incineration, minimizing the emission of greenhouse gases and other pollutants.

Solvent Recovery: The regeneration and reuse of solvents in the physical recycling process decreases the need to produce new solvents, further contributing to the reduction of environmental impact.

Economic advantages

Reduction of Operating Costs: Lower energy consumption and the possibility of recycling solvents reduce the operating costs of the physical recycling process compared to traditional methods.

Valorization of Recycled Materials: Polymers recycled through the physical recycling process maintain a high quality, allowing them to be sold at higher prices than materials recycled using traditional methods, thus bringing an economic advantage to operators in the sector.

Opening New Markets: The production of high-quality recycled plastic materials opens up new markets, including high-value-added sectors that have traditionally hesitated to use recycled materials due to quality concerns.

Challenges and Future Prospects

Despite its many benefits, physical recycling faces both technical and market challenges. The need for further research to optimize dissolution and separation processes, the adaptation of existing infrastructure and the creation of regulations that favor the adoption of innovative recycling technologies are among the main challenges to overcome.

However, the future outlook is promising, with the expectation that technological improvements and a growing commitment to sustainability will drive greater adoption of physical recycling.

Conclusions

Physical recycling emerges as a promising methodology in the field of polymer recycling, offering a sustainable alternative to traditional methods.

With its ability to produce high-quality recycled materials, reduce energy consumption and minimize environmental impact, physical recycling has the potential to play a crucial role in the circular economy of the future.

Its large-scale implementation could mark a significant step towards solving the global plastic waste crisis by aligning economic interests with environmental ones.

Scientific Publications on Physical Recycling

“Advanced Recycling of Polymers through Dissolution: An Overview of the Process and its Sustainability Impact” – This publication provides a detailed analysis of the physical recycling process through dissolution, discussing the choice of solvents, separation technologies and comparison of environmental impact compared to mechanical and chemical recycling.

“Solvent-based Recycling of Polyethylene Terephthalate: Towards Circular Economy” - Focusing on PET, this study explores the use of sustainable solvents for the physical recycling of the material, evaluating the effectiveness of the process in terms of quality of the recovered polymer and environmental sustainability .

“Separation Techniques for Mixed Polymer Waste: Enhancing the Sustainability of Plastic Recycling” - This article examines various techniques for separating polymer mixtures, with a particular focus on physical recycling. It offers a comparison with traditional methods and discusses future prospects for improving mixed plastic recycling.

These publications represent only a fraction of the ongoing research in the field of physical polymer recycling. The growing interest in this area promises further developments and innovations, with the aim of overcoming current challenges in the recycling of plastic materials and promoting greater sustainability in the industry.