PhD Research Position on Optimal Pre-Processing for Sustainable Dissolution Based Recycling

The objective of this PhD is the development of an innovative recycling process configuration, combining mechanical and chemical treatment steps, for selected end-of-life plastic waste materials for reuse in smart food containers. The challenges for this are big as plastic packaging is responsible for around 60% of post-consumer waste in the EU26, with currently ~173 kg of plastic waste generated per inhabitant. Therefore, the recycling of packaging material with an increasing uptake of recycled content has gained significant interest. Most recycling concepts for the end-of-life plastics are based on either (1) mechanical recycling necessitating closed loop collection systems to safeguard cleanliness and safety of the recycled material, or (2) pyrolysis to produce a bio-oil whereby the chemical identity of the initial polymers is lost, and the material is downcycled. 

There is thus a need on innovative recycling concepts whereby more complex waste streams can be recycled without losing the chemical identity and functionality of the plastic materials.

In the project, the most promising end-of life streams will first be characterized, evaluated and selected, then the optimal pre-treatment by mechanical sorting will be investigated, and finally a dissolution-based approach will be developed allowing to selectively recover the polymers from the pre-treated materials. Special attention will be paid to green solvents, with lower environmental impact, as compared to the more traditional solvents like xylene or THF. Suitable solvents will be selected based on VITO’s in-house comprehensive green solvents’ database. Removal of contaminants / additives hampering reuse for the targeted application will be an important focus.

In parallel, it is the objective to asses the eco friendliness of food-grade materials and to compare recycled with the virgin polymers and polylactic acid (PLA) from a product life cycle perspective, including longevity; in the current European regulatory context; making use of the real-world polymer-containing waste materials or combinations. For this different assessment methodologies will be considered include LCC, LCA, TEA and mSEA.