In the digital age, electronic devices have become indispensable elements in our daily lives, playing a key role in areas such as communication, work, education and entertainment. However, the widespread and growing use of these devices has led to an exponential increase in the generation of electronic waste, known as WEEE (waste electrical and electronic equipment).

Among other components, mobile phones, computers and household appliances in general contain a large amount of plastics. It is estimated that plastics account for approximately 20% of the total weight of e-waste.

While the metals present in these devices often dominate the recovery processes, plastics play a key role in their manufacture and functionality. However, at the end of their useful life, these plastics often become an environmental challenge that urgently needs to be addressed.

Many of these plastics are difficult to recycle due to their complex composition. They contain additives, such as halogens (especially chlorine and bromine compounds), which are used in the manufacture of housings, cables, components and flame retardants. These compounds not only make recycling difficult, but are also toxic and persistent in the environment, contaminating soil, water and air.

Why are plastics from WEEE not recycled?

Mechanical recycling, the most common method of processing plastics, is based on shredding and reprocessing the materials to create new products. This process requires plastics to be of a single type, clean and free of degradation.

However, plastics in this sector do not meet these conditions. They are heterogeneous mixtures, often contaminated with other materials and deteriorated after use. In addition, the presence of halogenated additives further complicates their recycling by conventional methods.

Faced with this challenge, scientific research is looking for innovative solutions for the recycling of WEEE plastics. At IMDEA Energía, we are exploring thermochemical processes, such as pyrolysis and hydropyrolysis, to transform these difficult-to-recycle plastics into valuable products by removing the halogens present.

Obtaining high-value products

Pyrolysis decomposes plastic waste at high temperatures in the absence of oxygen, generating three main products: oils, gases and a solid fraction called char. The oils obtained are the most valuable fraction, and can be used as fuel for transport or as raw material for the production of new plastics.

Hydropyrolysis, on the other hand, adds hydrogen to the process, which facilitates the elimination of impurities and improves the quality of the products obtained.

To optimise hydropyrolysis, we use catalysts, materials that enhance the chemical reactions and accelerate the elimination of halogens to levels of less than 0.001 % by weight in the oils produced. This low content allows them to be used in industrial applications without the risk of deactivating the catalysts used in modern refineries or causing corrosion damage to the facilities.

Our research at IMDEA Energía focuses on optimising different parameters of the hydropyrolysis process, such as reactor configuration, temperature, pressure and type of catalyst, to achieve maximum efficiency in the removal of halogens and the production of high value-added products. This work is part of the NONTOX project, which addresses the challenge of recycling plastics from WEEE from a scientific and social perspective.

Thanks to these techniques, it is possible to transform non-recyclable plastics into valuable products, while eliminating hazardous substances. This approach has the potential to significantly reduce plastic pollution and give a second life to electrical and electronic waste by obtaining high value-added products.

However, while the results are promising, some challenges remain. The process needs to be scaled up, its economic cost optimised and the efficiency and stability of the catalyst further improved to ensure its viability on a large scale.

Research at IMDEA Energía is driving new ways to recycle plastics from electrical and electronic waste, promoting a more sustainable management of these materials. In the long term, these innovative solutions have the potential to significantly reduce plastic pollution and optimise the use of the resources present in e-waste, thus contributing to building a cleaner and more sustainable future.

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