Wagland Stuart T, Canopoli Luisa, Coulon Frederic, Turner Diane Coral, Morgan Geraint Huw
Faculty of Engineering and Applied Sciences, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK.
Faculty of Engineering and Applied Sciences, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK.
Waste Manag. 2025 Aug 6;206:115035. doi: 10.1016/j.wasman.2025.115035.
This study evaluates the potential for producing valuable chemical products from plastics recovered from municipal solid waste (MSW) landfills and therefore contributing to waste reduction and resource recovery. Using pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) we analysed the decomposition products of 10 plastic samples including fresh and excavated samples of different landfill periods from 4 landfill sites. The samples comprised polyethylene (PE), polypropylene (PP), two mixed excavated plastic materials containing PE, PP, polystyrene (PS), poly(ethylene terephthalate) (PET) and poly(vinyl chloride) (PVC). All samples were pyrolyzed at 350, 500, 650 and 800 °C to semi-quantitatively identify the range of compounds produced at each temperature. Hydrocarbon production was the highest at 500 °C and 650 °C whit a significant proportion of the products falling within the naphtha range (C6-C10), which is a critical feedstock in the plastic industry. Notably, naphtha can be cracked to produce 55 wt% high-value chemicals, such as ethylene and propylene. Additionally, aromatic compounds such as benzene, toluene and styrene, especially in the mixed samples demonstrate potential for use in the chemical industries for polymers, solvents and dyes. These results provide encouraging evidence that excavated landfill plastics can serve as a viable source of valuable chemical intermediates, supporting both resource recovery and the advancement of a circular plastics economy. While this study offers an important initial assessment, primarily qualitative and focused on single polymers and controlled artificial mixtures, it establishes a solid foundation for future research. Further investigations using heterogeneous and larger-scale processing are recommended to fully demonstrate the techno-economic feasibility and environmental benefits of integrating pyrolysis of aged plastics into sustainable waste management and resource recovery strategies.
本研究评估了从城市固体废物（MSW）填埋场回收的塑料生产有价值化学产品的潜力，从而有助于减少废物和资源回收。我们使用热解-气相色谱-质谱联用仪（Py-GC-MS）分析了10个塑料样品的分解产物，这些样品包括来自4个填埋场不同填埋期的新鲜和挖掘出的样品。样品包括聚乙烯（PE）、聚丙烯（PP）、两种含有PE、PP、聚苯乙烯（PS）、聚对苯二甲酸乙二酯（PET）和聚氯乙烯（PVC）的混合挖掘塑料材料。所有样品在350、500、650和800℃下进行热解，以半定量地确定每个温度下产生的化合物范围。在500℃和650℃时烃产量最高，很大一部分产物属于石脑油范围（C6-C10），这是塑料工业中的关键原料。值得注意的是，石脑油可以裂解产生55 wt%的高价值化学品，如乙烯和丙烯。此外，苯、甲苯和苯乙烯等芳香族化合物，特别是在混合样品中，显示出在聚合物、溶剂和染料等化学工业中的应用潜力。这些结果提供了令人鼓舞的证据，表明挖掘出的填埋塑料可以作为有价值化学中间体的可行来源，支持资源回收和循环塑料经济的发展。虽然本研究提供了重要的初步评估，主要是定性的，且侧重于单一聚合物和受控人工混合物，但它为未来的研究奠定了坚实的基础。建议进一步开展使用非均相和大规模处理的研究，以充分证明将老化塑料热解纳入可持续废物管理和资源回收战略的技术经济可行性和环境效益。
