Synergistic Alkaline Hydrothermal Leaching Coupled with Toughening Modification for Debromination and Recycling of Waste BFR-Containing ABS Plastics

The upcycling of waste acrylonitrile-butadiene-styrene (ABS) plastic containing brominated flame retardants is an important part of achieving low-carbon and sustainable development. This study proposes a two-stage strategy combining alkaline hydrothermal leaching (AHL) pretreatment and blending modification to achieve efficient debromination and upcycling of waste BFR-containing ABS plastics. The alkaline hydrothermal method effectively disrupted the molecular structure of decabromodiphenyl ethane (DBDPE) flame retardants, enabling Br removal. Single-factor experiments optimized the AHL parameters, achieving a debromination efficiency of 92.86% (from 52,364 to 3741 mg/kg) for BFR-containing ABS waste under conditions where the leaching condition was maintained at 240 °C and 0.6 h. Subsequent blending modification with virgin ABS and a toughening agent significantly enhanced the mechanical properties of the BFR-containing plastics, yielding recycled materials with physical performance comparable to virgin resins while further diluting residual Br concentrations from 3741 to 855 mg/kg. This approach addressed the critical challenge of property degradation in alkali-treated plastics, enabling their practical reuse. The synergistic integration of AHL and blending modification not only achieved efficient Br removal but also restored the material’s functionality, establishing a sustainable pathway for recycling hazardous BFR-containing ABS wastes.