A research team led by Professor Kotohiro Nomura at Tokyo Metropolitan University has developed a groundbreaking method for the depolymerization of polyethylene terephthalate (PET) using alcohols and a cost-effective iron trichloride (FeCl3) catalyst. This innovative technique facilitates selective chemical recycling of textile and plastic waste mixtures, addressing the pressing issue of plastic waste. The findings are published in the journal Industrial Chemistry & Materials.
Plastic pollution remains a critical environmental challenge, with current recycling rates, particularly for chemical recycling, being alarmingly low. Polyester, commonly found in plastic bottles and clothing, can be reverted to its raw materials by breaking its ester bonds. Traditional methods for achieving this typically require high temperatures and substantial amounts of acidic or basic substances, which can be environmentally detrimental.
The newly developed method utilizes acid- and base-free catalytic depolymerization of PET with ethanol, employing FeCl3 or FeBr3 as catalysts, and operates effectively at temperatures of 160–180ºC. The process yields diethyl terephthalate (DET) and ethylene glycol (EG) with remarkable selectivity rates of 98–99%. Notably, this approach enables the exclusive and selective depolymerization of PET from textile waste, which often consists of both PET and cotton. The method allows for the quantitative recovery of cotton while successfully recycling PET from mixed plastic waste.
This advancement represents a significant step toward a circular economy, offering a straightforward and environmentally friendly solution for the chemical recycling of PET, particularly from textile waste. The research emphasizes the potential for scaling up this method to address the growing demand for sustainable recycling solutions in the textile and plastic industries.
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