Near-quantitative recycling of polyethylene terephthalate waste to plastic-like polymer via microwave-assisted Zn-Zr/ZnO catalysis

Zr-Zn/ZnO catalyst was synthesized for microwave-assisted PET glycolysis. • Atomic-level Zr incorporation regulates Zn coordination environments and Lewis acidity. • Near-quantitative recycling of PET waste was achieved. • Synergistic Zn Zr sites facilitate PET glycolysis toward high-purity BHET (99.8%). • This strategy can potentially be applied to diverse real-world PET waste. Closed-loop recycling of polyethylene terephthalate (PET) into bis(2-hydroxyethyl) terephthalate (BHET) monomers represents a promising approach to plastic waste valorization, yet its application is constrained by low monomer purity and limited feedstock compatibility. Herein, a high-performance Zn-Zr/ZnO catalyst was synthesized via a simple impregnation method. Under microwave-assisted glycolysis conditions, this catalyst enables the conversion of PET to BHET with a yield of 94.2% and purity of 99.8%. The system demonstrates stable recyclability over 10+ reaction cycles and reduces energy consumption by 60% in the depolymerization process compared with conventional electric furnace-based thermal catalysis. The recovered BHET can be repolymerized into a PET-like polymer, establishing a closed-loop material cycle. Notably, the method achieves efficient monomer conversion across a range of real-world PET plastics and fiber products, with successful implementation in a 150-g scale-up experiment. Mechanistic studies indicate that Zr and Zn species synergistically promote PET depolymerization to BHET. This work presents an efficient and stable route for high-value closed-loop recycling of waste PET, which could support the advancement of the plastic circular economy. Download: Download high-res image (317KB) Download: Download full-size image