Nanoarchitectonics of ZnFe-Layered Double Hydroxide Catalysts for Valorization of Waste Polyethylene Terephthalate Bottles into Value-Added Products.

Human reliance on plastic has increased plastic waste generation. Polyethylene terephthalate (PET) is one of the major commodity plastics used and shows long persistence in nature, causing environmental threats. To mitigate this problem of pollution, a highly efficient ZnFe-layered double hydroxide has been synthesized via the hydrothermal method for valorization of waste PET bottles to bis(2-hydroxyethyl) terephthalate (BHET) by glycolysis. A comprehensive structural, compositional, morphological, and surface analysis characterizations were performed to get deep insights into its properties. The developed reaction protocol for the glycolysis of PET has been optimized by varying the reaction parameters, including catalyst amount, time, temperature, and amount of ethylene glycol. Different types of colored waste plastic bottles were used for glycolysis to evaluate the generality of the developed reaction protocol. Additionally, various alcohols were employed for alcoholysis, resulting in the formation of their monomeric compounds using the ZnFe-layered double hydroxide catalyst, which indicates its broad scope. Furthermore, various control reactions were performed to investigate the role of acidic and basic sites, which are crucial for catalytic activity. In addition, green metric parameters were calculated to determine the greenness of the developed protocol. This work provides a green and sustainable strategy for the valorization of waste PET.