Understand The New Recycling Process Of Waste Polyester Plastics

Fu Yao, a professor of the University of Science and Technology of China, and Deng Jin, an associate researcher, together with Shen Li, a professor of the University of Utrecht in the Netherlands, reported a scheme to upgrade and recycle waste PET plastics through chemical depolymerization of acetic acid. Relevant achievements have been published in Nature Communication.

PET plastic has brought great convenience to human life, but it is also faced with problems such as large consumption and recycling difficulties. The current mature PET recycling method can realize the degradation recycling from waste beverage bottles to polyester textiles. However, due to the limitation of process technology and production cost, it is difficult to realize recycling and upgrading recovery in industry at present.

Researchers used acetic acid to depolymerize waste PET plastics. The depolymerization of PET in organic acids experienced a process of melting dissolution precipitation. Through the acetic acid depolymerization program, efficient recovery from various waste PET materials to high-purity terephthalic acid can be directly realized. Another product of PET acetic acid depolymerization is the third generation environmental friendly strong solvent ethylene glycol diacetate with high added value. The preparation scheme of waste PET materials from acetic acid depolymerization has a strong economic attraction for the production of commonly used industrial raw materials terephthalic acid and ethylene glycol diacetate.

On this basis, the researchers put forward the technical scheme of "depolymerization polymerization regeneration of waste PET acetic acid" closed-loop cycle, and carried out a life cycle assessment of the process. The results show that compared with the process of preparing PET polyester from fossil resources, the non renewable energy consumption and global warming potential of this process are reduced by more than 70% and 40% respectively, which is the lowest environmental impact among all PET chemical recovery methods at present.

The researchers introduced that this research provides a new way to realize the closed-loop cycle of waste PET plastics and polyester fabrics with low industrial cost, strong economic attraction, more green and low-carbon treatment process, and stronger resistance to raw material sources.