柴油机烟灰颗粒的热失活对柴油机颗粒过滤器(DPF)再生的控制策略具有重要影响。这项工作的重点是表面官能团的变化,碳化学状态,以及在600°C的中间温度下在惰性气体环境中进行热处理时的石墨化程度,800°C,和1000°C,并使用热重分析仪和气相色谱质谱仪(TGA-GC/MS)探索在热处理过程中从柴油烟灰表面解吸的化学物质。使用傅里叶变换红外光谱(FT-IR)和X射线光电子能谱(XPS)表征了表面官能团和碳化学状态。通过拉曼光谱(RS)评价石墨化程度。脂肪族C-H的浓度,C-OH,C=O,和O-C=O基团减少柴油烟灰和炭黑时,提高热处理温度,而sp2/sp3杂化比和石墨化程度增强。这些结果提供了烟灰样品反应性降低的全面证据。在含氧官能团中,对于O-C=O基团,由于其最差的热力学稳定性,在热处理期间的百分比降低是最大的。TGA-GC/MS结果表明,在柴油烟灰的1000°C热处理过程中,脂肪族和芳香族链以及含氧物种会从烟灰表面解吸。
The thermal deactivation of diesel soot particles exerts a significant influence on the control strategy for the regeneration of diesel particulate filters (DPFs). This work focused on the changes in the surface functional groups, carbon chemical state, and graphitization degree during thermal treatment in an inert gas environment at intermediate temperatures of 600°C, 800°C, and 1000°C and explore the chemical species that were desorbed from the diesel soot surface during thermal treatment using a thermogravimetric analyser coupled with a gas-chromatograph mass spectrometer (TGA-GC/MS). The surface functional groups and carbon chemical state were characterized using Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The graphitization degree was evaluated by means of Raman spectroscopy (RS). The concentrations of aliphatic C-H, C-OH, C=O, and O-C=O groups are reduced for diesel soot and carbon black when increasing the thermal treatment temperature, while the sp2/sp3 hybridized ratio and graphitization degree enhance. These results provide comprehensive evidence of the decreased reactivity of soot samples. Among oxygenated functional groups, the percentage reduction during thermal treatment is the largest for the O-C=O groups owing to its worst thermodynamic stability. TGA-GC/MS results show that the aliphatic and aromatic chains and oxygenated species would be desorbed from the soot surface during 1000°C thermal treatment of diesel soot.