Morphology, structure and chemistry of extracted diesel soot: Part II: X-ray absorption near edge structure (XANES) spectroscopy and high resolution transmission electron microscopy

Chemical composition of diesel soot extracted from used diesel engine has been investigated using X-ray Absorption Near Edge Structure (XANES) spectroscopy and high-resolution transmission electron microscopy (HRTEM). The XANES spectra indicate the presence of phosphates of zinc and calcium and sulfates of zinc and calcium as well as the presence of sulfides of zinc. HRTEM coupled with EDS and lattice imaging indicates the presence of nanoparticles of Ca3(PO4)2 and Fe2O3 embedded in the turbostratic soot structure. Both Ca3(PO4)2 and Fe2O3 are hard particles and appear to have been incorporated within the turbostratic soot structure during third body wear.

► We examine comprehensively the structure and properties of soot extracted from a EGR engine.
► XANES indicates the presence of Zn-phosphates and sulfates of Ca and Zn.
► HRTEM indicates that Fe2O3 and Ca-phosphates are incorporated into the soot structure.
► A phenomenological model has been proposed to explain the structure of EGR diesel soot.