The accumulation of plastic waste in the environment is rising and poses a significant environmental and health threat. Polyethylene terephthalate (PET), used mainly in single-use plastic bottles, accounts for a substantial fraction of this waste. The currently employed recycling strategies are inadequate to deal with the global plastic waste problem. PET glycolysis is a promising depolymerization method but has mainly been conducted using homogeneous catalysts; developing active and sustainable catalysts, and more energy-efficient processes remain challenges. Here, we implement microwave heating in PET glycolysis and identify ZnO as an excellent heterogeneous catalyst. We demonstrate the influence of ZnO's particle size and facet and hydrogen bonding on its activity. Finally, we demonstrate excellent performance for real-world post-consumer PET waste deconstruction with rapid depolymerization into bis(2-hydroxyethyl) terephthalate (BHET), achieving > 95% yields in less than 10 min. Cradle-to-gate life cycle assessment also indicates that BHET produced by ZnO-catalyzed glycolysis has lower global warming potential than the petrochemical-based production and homogeneously-catalyzed glycolysis.

中文翻译：

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多相催化剂上微波辅助 PET 解聚


环境中塑料废物的积累不断增加，对环境和健康构成重大威胁。聚对苯二甲酸乙二醇酯 (PET) 主要用于一次性塑料瓶，占此类废物的很大一部分。目前采用的回收策略不足以解决全球塑料废物问题。 PET 糖酵解是一种很有前景的解聚方法，但主要使用均相催化剂进行；开发活性和可持续的催化剂以及更节能的工艺仍然是挑战。在这里，我们在 PET 糖酵解中实施微波加热，并确定 ZnO 是一种优异的多相催化剂。我们证明了 ZnO 的粒径、晶面和氢键对其活性的影响。最后，我们展示了现实世界中消费后 PET 废物解构的优异性能，可快速解聚为对苯二甲酸双（2-羟乙基）酯 (BHET)，在不到 10 分钟的时间内实现 > 95% 的产率。从摇篮到大门的生命周期评估还表明，与石化生产和均相催化糖酵解相比，ZnO 催化糖酵解生产的 BHET 具有更低的全球变暖潜力。