Highly efficient kilogram-scale mechanochemical catalytic depolymerization of PET polyester waste into reusable monomers

Efficient chemical upcycling of polyethylene terephthalate (PET) waste into value-added chemicals has attracted considerable attention in a broad range of environmental and energy fields. The mechanochemical depolymerization of PET waste emerges as a potential approach for large-scale industrial applications, enabling the conversion of PET waste into reusable monomers. Herein, we conducted a pilot-scale test by depolymerization of 1 kg of PET waste in a planetary ball mill. The incremental optimization of the depolymerization process was investigated systematically by adjusting parameters such as the type of ball mill, the ratio of liquid volume to solid mass, the grinding jars, and the milling frequency. Remarkably, monomers with a yield of more than 97 % when converting kilogram-scale PET waste, including used textiles and plastic bottles, were achieved in a planetary ball mill at 400 rpm for 80 min. This notable enhancement will substantially benefit future potential industrial-scale applications.