Researchers Develop Zn Catalyst for Closed-Loop Recycling of Polyester Waste

Researchers at the University of California, Berkeley, and collaborators have developed a new catalyst for recycling polyester waste. The catalyst uses coordinatively unsaturated zinc sites to depolymerize polyethylene terephthalate (PET) into its monomers, terephthalic acid and ethylene glycol. This approach allows for the recovery of high-purity materials suitable for repolymerization.

The study, published in Nature Communications on October 15, 2024, details the catalyst's performance under mild conditions. It operates at temperatures below 200 degrees Celsius and atmospheric pressure, reducing energy requirements compared to traditional methods. com reported that the process achieves over 95% conversion efficiency for post-consumer PET waste.

The zinc catalyst features unsaturated coordination sites that enhance its activity in breaking ester bonds in polyester chains.

This design draws from bioinspired models, mimicking enzymes that degrade natural polymers. The researchers tested the catalyst on various polyester sources, including textile waste and plastic bottles. Experimental results showed that the recycled monomers match the quality of virgin materials, enabling direct reuse in manufacturing new polyester products.

The method avoids harsh chemicals used in conventional hydrolysis or glycolysis processes. No significant byproducts were observed, according to the study.

Context Polyester, primarily PET, constitutes a large portion of global plastic waste, with over 70 million tons produced annually.

Current recycling rates for PET remain below 30% in many regions, contributing to landfill accumulation and microplastic pollution. This new technique addresses these challenges by facilitating closed-loop recycling, where waste becomes a resource. Stakeholders include textile manufacturers, packaging companies, and waste management firms.