Ha Do Tuong, Tong Hien Duy, Trinh Thuat T
Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
Faculty of Engineering, Vietnamese-German University (VGU), Thu Dau Mot City, Binh Duong Province, Vietnam.
Sci Rep. 2024 Aug 13;14(1):18771. doi: 10.1038/s41598-024-69337-z.
Microplastics have become a pressing environmental issue due to their widespread presence in our ecosystems. Among various plastic components, polyethylene (PE) is a prevalent and persistent contaminant. Hydrothermal gasification (HTG), a promising technology for converting PE into syngas, holds great promise for mitigating the microplastic problem. In this study, we employ ReaxFF molecular dynamics simulations to investigate the HTG process of PE, shedding light on the intricate relationships between temperature, water content, carbon conversion efficiency, and product distributions. The results reveal that hydrothermal gasification of PE is a complex process involving multiple reaction pathways. Consistently with experimental findings, the calculations indicate that the gas phase exhibits a substantial hydrogen fraction, reaching up to 70%. Interestingly, our simulations reveal a dual role of water content in the HTG process. On one hand, water enhances hydrogen production by promoting the gas formation. On the other hand, it elevates the activation energy required for PE decomposition. Depending on the water content, the calculated activation energies range from 176 to 268 kJ/mol, which are significantly lower than those reported for thermal gasification (TG). This suggests that HTG may be a more efficient route for PE conversion. Furthermore, this study highlights the importance of optimizing both temperature and water content in HTG systems to achieve high yields of hydrogen-rich syngas. The results obtained from our ReaxFF MD simulations demonstrate the robustness of this computational methodology in elucidating complex chemical reactions under extreme conditions. Our findings offer critical insights into the design of advanced waste management strategies for microplastics and contribute to the development of sustainable practices for resource recovery. This work underscores the potential of HTG as a key technology for addressing the global challenge of plastic pollution.
由于微塑料在我们的生态系统中广泛存在，它们已成为一个紧迫的环境问题。在各种塑料成分中，聚乙烯（PE）是一种普遍且持久的污染物。水热气化（HTG）是一种将PE转化为合成气的有前景的技术，对于缓解微塑料问题具有很大的潜力。在本研究中，我们采用ReaxFF分子动力学模拟来研究PE的HTG过程，揭示温度、含水量、碳转化效率和产物分布之间的复杂关系。结果表明，PE的水热气化是一个涉及多个反应途径的复杂过程。与实验结果一致，计算表明气相中氢的比例相当高，可达70%。有趣的是，我们的模拟揭示了含水量在HTG过程中的双重作用。一方面，水通过促进气体形成来提高氢气产量。另一方面，它提高了PE分解所需的活化能。根据含水量的不同，计算出的活化能范围为176至268 kJ/mol，这明显低于热气化（TG）报道的活化能。这表明HTG可能是PE转化的更有效途径。此外，本研究强调了优化HTG系统中的温度和含水量以实现高产率的富氢合成气的重要性。我们从ReaxFF MD模拟中获得的结果证明了这种计算方法在阐明极端条件下复杂化学反应方面的稳健性。我们的研究结果为微塑料的先进废物管理策略设计提供了关键见解，并有助于开发可持续的资源回收实践。这项工作强调了HTG作为应对全球塑料污染挑战的关键技术的潜力。
