Zhang Yongliang, Zhan Lu, Xu Zhenming
School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
National Observation and Research Station of Erhai Lake Ecosystem in Yunan, Dali 671000, China.
Environ Sci Technol. 2025 Jan 14;59(1):935-944. doi: 10.1021/acs.est.4c09178. Epub 2024 Dec 24.
The extensive use and longevity of nylon plastics pose substantial challenges for plastic management, recycling, and pollution control. Depolymerization and monomer recycling are potential solutions for valorizing waste plastics, but they often rely on complex and costly catalysts. Additionally, various additives in nylon plastics can negatively impact the catalyst efficiency. To address these issues, we proposed a novel method of hydrothermal clean water depolymerization without any catalysts. In this study, high-purity monomers were successfully recovered from nylon plastics by utilizing the reversibility and hydrophilicity of amide bonds, with hydrothermal amphoteric hydrolysis applied as the method. On this basis, repolymerization of the monomer was completed, and new nylon was generated by one-pot solution polycondensation, thereby achieving a closed-loop recycling process. A depolymerization model was established for nylon in a hydrothermal system at both macro- and micro levels, revealing a unique mechanism of simultaneous surface and internal depolymerization. This process enables the closed-loop upcycling of nylon, transforming waste back into its starting materials, reducing carbon emissions, and promoting sustainability.
尼龙塑料的广泛使用和长寿命给塑料管理、回收利用及污染控制带来了巨大挑战。解聚和单体回收是使废塑料增值的潜在解决方案，但它们通常依赖复杂且昂贵的催化剂。此外，尼龙塑料中的各种添加剂会对催化剂效率产生负面影响。为解决这些问题，我们提出了一种无需任何催化剂的水热清洁水解聚新方法。在本研究中，利用酰胺键的可逆性和亲水性，通过水热两性水解法成功从尼龙塑料中回收了高纯度单体。在此基础上，完成了单体的再聚合，并通过一锅法溶液缩聚生成了新的尼龙，从而实现了闭环回收过程。在宏观和微观层面建立了水热体系中尼龙的解聚模型，揭示了独特的表面和内部同时解聚机制。该过程实现了尼龙的闭环升级循环，将废物转化回其起始原料，减少碳排放，促进可持续发展。
