Physicochemical Characteristics of Particulate Matter Emitted from the Oxygenated Fuel/Diesel Blend Engine

Abstract The physicochemical characteristics of particulate matter (PM) produced by polyoxymethylene dimethyl ethers (PODE2–4)/diesel blended fuel at different blend ratios was characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). TEM analysis indicated that the overall size of PM decreased with an increasing PODE2–4 concentration. TEM images using fractal theory showed that the fractal dimension of PM increased as the PODE2–4 blending ratio increased. These trends increased the oxidation activity. FTIR was used to analyze the aliphatic C-H on the surface of PM and found that the ratio IC-H/IC=C and the aliphatic C-H functional group on the surface of PM decreased with an increasing PODE2–4 blending ratio. According to XPS data, with increments of the PODE2–4 blending ratio, the contents of O/C, sp3/sp2, C-OH, C=O and total oxygen-containing functional groups of the PM increased, demonstrating that the oxygen-containing functional group and disorder of the PM nanostructure was correlated with a faster oxidation rate. Results thus demonstrated that the addition of PODE2–4 can affect the nanostructure and oxidation activity of PM, making it easier to oxidize to reduce environmental pollution.