Impact of carbon chain length of alcohols on the physicochemical properties and reactivity of exhaust soot

Mingzhang Pan; Yuke Wang; Jiangjun Wei; Haozhong Huang; Xiaorong Zhou

doi:10.1016/j.scitotenv.2021.149434

Impact of carbon chain length of alcohols on the physicochemical properties and reactivity of exhaust soot

Sci Total Environ. 2021 Dec 10:799:149434. doi: 10.1016/j.scitotenv.2021.149434. Epub 2021 Aug 3.

Authors

Mingzhang Pan¹, Yuke Wang¹, Jiangjun Wei², Haozhong Huang³, Xiaorong Zhou¹

Affiliations

¹ College of Mechanical Engineering, Guangxi University, Nanning 530004, China.
² School of Automotive and Transportation Engineering, Hefei University of Technology, No.193 Tunxi Road, Hefei, China. Electronic address: wjiangjun@hfut.edu.cn.
³ College of Mechanical Engineering, Guangxi University, Nanning 530004, China. Electronic address: hhz421@gxu.edu.cn.

PMID: 34371412
DOI: 10.1016/j.scitotenv.2021.149434

Abstract

Particle is the main pollutant in diesel engine exhaust, which seriously endangers human health and the atmospheric environment. The use of alcohol fuels in diesel engines can effectively reduce particle emissions, but alcohol fuels with different carbon chain lengths will affect the generation process of particles, which in turn changes the physicochemical properties and oxidation characteristics of the particles. Therefore, it is particularly important to study the properties of particle emitted by diesel engines fueling alcohol fuels with different carbon chain lengths. The physicochemical properties of soot emitted from commercial diesel engines were studied by thermogravimetric analyzer, HRTEM (high-resolution transmission electron microscopy), and XPS (X-ray photoelectron spectroscopy) in this paper, respectively. The diesel engine used alcohol-diesel blends of different carbon chain lengths with the same oxygen content as fuels, such as methanol/diesel blend (M10), n-butanol/diesel blend (NB25), and n-octanol/diesel blend (NO45), and pure diesel fuel was used as a reference. The results showed that the use of alcohols reduced the fractal dimension (D_f) of particles, and the NB25 particles had the smallest D_f. Moreover, the particles of blended fuels had smaller primary particle diameter (d_p) compared to pure diesel. However, with the use of short-chain to long-chain alcohols, an increasing tendency of d_p was observed. In terms of the nanostructure, as the use of short-chain to long-chain alcohols, the L_a (fringe length) increased, both the d (fringe separation distance) and T_f (fringe tortuosity) reduced, which was not favorable for the oxidation of the particles. In addition, in terms of oxygenated surface functional groups (SFGs), the CO group occupied a higher proportion in most working conditions relative to the groups of CO and COO. Further analysis showed that the d_p and nanostructure had more influence on the oxidation behavior of soot than D_f and oxygenated SFGs.

Keywords: Different alcohols-diesel fuels; Morphology; Nanostructure; Oxygenated functional groups.

MeSH terms

Carbon
Ethanol
Gasoline / analysis
Humans
Soot* / analysis
Vehicle Emissions* / analysis

Substances

Gasoline
Soot
Vehicle Emissions
Ethanol
Carbon