Au cours des cinq prochaines annĂ©es, la terre atteindra huit milliards d’habitants. Les chercheurs d'IBM du monde entier travaillent sur des solutions Ă  chaque Ă©tape de la chaĂ®ne alimentaire. Ces innovations ont Ă©tĂ© prĂ©sentĂ©es lors de l’évĂ©nement Science Slam organisĂ© par IBM Ă  San Francisco : Think 2019 (research.ibm.com/5-in-5)

• VolCAT : procĂ©dĂ© chimique catalytique qui digère les plastiques polyesters en une substance pouvant ĂŞtre directement rĂ©injectĂ©e dans les machines de production de plastique afin de fabriquer de nouveaux produits. Ci-dessous prĂ©sentation du procĂ©dĂ© par IBM.

«Plastic waste is plaguing our planet. In total, people have produced more than 8 billion metric tons of plastic. Half of all newly manufactured plastic becomes trash in less than a year.

By 2050, there is projected to be more plastic in the ocean than fish.

PET is one of the most common manufactured plastic polymers (~10% of total plastics produced per year), a key ingredient in food and beverage packages and in the fibers of cloth. Historically, most of this material was not recycled, a primary reason that 8 million metric tons of PET plastics are estimated to go into the ocean each year.

This is where advancements in plastics recycling like VolCat—short for volatile catalyst—come in. Plastic bottles, containers, and PET-based fabrics are collected, ground up, and combined with a chemical catalyst in a pressure cooker set to above 200 degrees Celsius. With heat and a small amount of pressure, the catalyst is able to digest and clean the ground-up plastic, and the process separates contaminants (e.g., food residue, glue, dirt, dyes, and pigments) from material that is useable for new PET. The useable matter (called a monomer) takes the form of a white powder, which can be fed directly into a polyester reactor to make brand new plastics.

In the coming years, advancements like VolCat will make plastics recycling more efficient and more versatile in treating more material types than its predecessors. Unlike traditional mechanical recycling, future plastics recycling will break down both colored and clear plastics, as well as dirty and clean containers, producing a high-quality final product that is 100 percent recyclable. (Mechanical recycling can only be used on clear, pre-cleaned containers and results in a material that’s only reusable when combined with new PET).

In the case of PET recycling. VolCat begins by heating PET and ethylene glycol in a reactor with the catalyst. After depolymerization is complete, the catalyst is recovered by distillation from the reactor using the heat of reaction. The solution is filtered, purified, and then cooled, and the solid monomer product is recovered by filtration. The recovered liquid, along with the catalyst, is then reintroduced into the depolymerization reactor in an energy-efficient cycle.

The team of researchers behind VolCat imagine the system being used at recycling and polyester manufacturing plants worldwide. Currently, polyester reactors are fed ingredients derived from petroleum. In five years, recyclers could cut out the fossil fuels, and simply attach a VolCat system to the assembly line and make new plastic directly from the old».

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