Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province, Kunming University of Science and Technology, Kunming, 650093, China; National Engineering Research Center of Vacuum Metallurgy, Kunming University of Science and Technology, Kunming, 650093, China; Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, 650093, China.
Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province, Kunming University of Science and Technology, Kunming, 650093, China; National Engineering Research Center of Vacuum Metallurgy, Kunming University of Science and Technology, Kunming, 650093, China; Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, 650093, China.
Environ Res. 2023 Dec 1;238(Pt 1):117071. doi: 10.1016/j.envres.2023.117071. Epub 2023 Sep 3.
As the accumulation of waste tires continues to rise year by year, effectively managing and recycling these discarded materials has become an urgent global challenge. Among various potential solutions, pyrolysis stands out due to its superior environmental compatibility and remarkable efficiency in transforming waste tires into valuable products. Thus, it is considered the most potential method for disposing these tires. In this work, waste tire powder is pyrolyzed at 560 °C to yield pyrolysis carbon black, and meanwhile, the purification effects of base-acid solutions on pyrolysis carbon black are discussed. High-purity few-layer graphene flakes and carbon nanohorns are synthesized by a direct current arc plasma with H and N as buffer gases and high-purity pyrolysis carbon black as raw material. Under an H atmosphere, hydrogen effectively terminates the suspended carbon bonds, preventing the formation of closed structures and facilitating the expansion of graphene sheets. During the preparation of carbon nanohorns, the nitrogen atoms rapidly bond with carbon atoms, forming essential C-N bonds. This nitrogen doping promotes the formation of carbon-based five-membered and seven-membered rings and makes the graphite lamellar change in the direction of towards negative curvature. Consequently, such change facilitates the formation of conical structures, ultimately yielding the coveted carbon nanohorns. This work not only provides an economical raw material for efficient large-scale synthesis of few-layer graphene and carbon nanohorns but also broadens the intrinsic worth of pyrolysis carbon black, which is beneficial to improving the recycling value of waste tires.
随着废旧轮胎的逐年积累，有效地管理和回收这些废弃材料已成为全球紧迫的挑战。在各种潜在的解决方案中，热解因其卓越的环境兼容性和将废旧轮胎转化为有价值产品的高效性而脱颖而出。因此，它被认为是处理这些轮胎最有潜力的方法。在这项工作中，将废轮胎粉末在 560°C 下进行热解，得到热解炭黑，同时讨论了酸碱溶液对热解炭黑的纯化效果。通过直流电弧等离子体，以 H 和 N 作为缓冲气体，以高纯度热解炭黑为原料，合成了高纯少层石墨烯片和碳纳米角。在 H 气氛下，氢有效地终止悬浮的碳键，防止形成封闭结构，并有利于石墨烯片的扩展。在制备碳纳米角的过程中，氮原子迅速与碳原子结合，形成必要的 C-N 键。这种氮掺杂促进了碳基五元环和七元环的形成，并使石墨层沿负曲率方向发生变化。因此，这种变化有利于锥形结构的形成，最终得到理想的碳纳米角。这项工作不仅为高效、大规模合成少层石墨烯和碳纳米角提供了经济的原料，还拓宽了热解炭黑的固有价值，有利于提高废旧轮胎的回收价值。
