Abstract
Poly(lactic acid) (PLA), a biodegradable plastic derived from starch, has gained prominence as a sustainable alternative to petroleum‐based plastics. However, the slow degradation of PLA in natural environments and contamination of recycling streams due to incompatibility with other plastics, highlight the need for efficient recycling techniques. This study reports a closed‐loop PLA recycling strategy by hydrolysis depolymerisation under moist‐solid condition and recovery of the valuable monomer lactic acid. By employing ball milling and resonance acoustic mixing, we investigate the effects of milling speed, time, ball size, alkali type, and ageing on lactate yield, to optimise the performance and demonstrate the efficiency of mechanical and moist‐solid conditions in polymer chain scission without bulk heating. Furthermore, we integrate a bipolar membrane electrodialysis process for conversion of lactate to lactic acid with simultaneous NaOH production, enhancing the sustainability of the recycling process. Life cycle assessment (LCA) was employed to assess the environmental impact of such PLA recycling approach for lactic acid production and provide recommendations for future improvements. This work demonstrates the effectiveness and environmental benefits of mechanically induced moist‐solid chemical recycling and integration with advanced membrane separation processes, offering a promising pathway for sustainable PLA waste management and lactic acid production.