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Thermally induced variations in the nanostructure and reactivity of soot particles emitted from a diesel engine
Chemosphere ( IF 8.8 ) Pub Date : 2021-07-29 , DOI: 10.1016/j.chemosphere.2021.131712
Ye Liu 1 , Chenyang Fan 2 , Xin Wang 2 , Fangjie Liu 2 , Haibo Chen 1
Affiliation  

This work focuses on the thermally induced variation in the nanostructure, size of primary particles and oxidative reactivity of diesel soot and a commercial carbon black in an inert gas environment at temperatures ranging from 600 to 1000 °C. Soot nanostructure and size were characterized by high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The soot reactivity was evaluated with respect to activation energy (Ea) and characteristic oxidation temperature, including peak temperature (TP) and burnout temperature (Tb), using thermogravimetric analysis (TGA). The mass loss of diesel soot and carbon black rises when increasing the thermal treatment temperature, especially at 1000 °C, and a significant quantity of mass loss can be observed, which is primarily due to thermal fragmentation and the desorption of chemical species on soot surfaces. The HRTEM and XRD results all indicate that the thermally treated soot samples have more ordered nanostructure than the untreated samples. There is a reduction in the size of primary particles as thermal treatment temperature increases. The soot reactivity decreases after thermal treatment, as manifested by the elevation in Ea, TP, and Tb values. Moreover, the oxidation reactivity of soot samples is closely associated with the fringe length, tortuosity, and fringe tortuosity. Compared to carbon black, diesel soot with a more disorder structure has a higher oxidative reactivity.



中文翻译:

柴油发动机排放的烟尘颗粒的纳米结构和反应性的热致变化

这项工作的重点是在惰性气体环境中,在 600 到 1000 °C 的温度下,柴油烟灰和商业炭黑的纳米结构、初级粒子的大小和氧化反应性的热致变化。烟尘纳米结构和尺寸通过高分辨率透射电子显微镜 (HRTEM) 和 X 射线衍射 (XRD) 进行表征。根据活化能 ( E a ) 和特征氧化温度,包括峰值温度 ( T P ) 和燃尽温度 ( T b),使用热重分析 (TGA)。随着热处理温度的升高,柴油机烟灰和炭黑的质量损失增加,尤其是在 1000 °C 时,可以观察到大量的质量损失,这主要是由于热裂解和烟灰表面化学物质的解吸. HRTEM 和 XRD 结果均表明,热处理后的烟尘样品比未处理的样品具有更有序的纳米结构。随着热处理温度的升高,初级颗粒的尺寸减小。热处理后烟灰反应性降低,表现为E aT PT b升高值。此外,烟尘样品的氧化反应性与条纹长度、曲折度和条纹曲折度密切相关。与炭黑相比,具有更无序结构的柴油烟尘具有更高的氧化反应性。

更新日期:2021-07-30
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