Influence on the oxidative potential of a heavy-duty engine particle emission due to selective catalytic reduction system and biodiesel blend

Abstract

Although the particulate matter (PM) emissions from biodiesel fuelled engines are acknowledged to be lower than those of fossil diesel, there is a concern on the impact of PM produced by biodiesel to human health. As the oxidative potential of PM has been suggested as trigger for adverse health effects, it was measured using the Electron Spin Resonance (OP(ESR)) technique. Additionally, Energy Dispersive X-ray Fluorescence Spectroscopy (EDXRF) was employed to determine elemental concentration, and Raman Spectroscopy was used to describe the amorphous carbon character of the soot collected on exhaust PM from biodiesel blends fuelled test-bed engine, with and without Selective Catalytic Reduction (SCR). OP(ESR) results showed higher oxidative potential per kWh of PM produced from a blend of 20% soybean biodiesel and 80% ULSD (B20) engine compared with a blend of 5% soybean biodiesel and 95% ULSD (B5), whereas the SCR was able to reduce oxidative potential for each fuel. EDXRF data indicates a correlation of 0.99 between concentration of copper and oxidative potential. Raman Spectroscopy centered on the expected carbon peaks between 1100cm(-1) and 1600cm(-1) indicate lower molecular disorder for the B20 particulate matter, an indicative of a more graphitic carbon structure. The analytical techniques used in this study highlight the link between biodiesel engine exhaust and increased oxidative potential relative to biodiesel addition on fossil diesel combustion. The EDXRF analysis confirmed the prominent role of metals on free radical production. As a whole, these results suggest that 20% of biodiesel blends run without SCR may pose an increased health risk due to an increase in OH radical generation.

Characterization and comparison of oxidative potential of real-world biodiesel and petroleum diesel particulate matter emitted from a nonroad heavy duty diesel engine

“…In addition to the differences in size cuts, the variability between these studies is likely due to variability in waste grease feedstock, compared to biodiesel made from pure rapeseed oil or soybean oil. Other researchers have also attributed fuel source as an important contributing factor to the concentrations of specific metals like Cr, Cu, Mn in PM from biodiesel and diesel exhaust (Gangwar et al 2012;Godoi et al 2016). Gangwar et al (2012) found that B20 PM (biodiesel from karanja oil) contained higher concentrations of Fe, Mn, and Cr, whereas the Cu concentration in diesel PM was higher.…”

“…2013;Traviss et al 2014;Pourkhesalian et al 2015). Reactive metals and various organic species may influence the oxidative potential of PM (Cheung et al 2010;Charrier and Anastasio 2012;Fukagawa et al 2013;Fang et al 2015;Totlandsdal et al 2015;Godoi et al 2016); however, understanding the relationship between PM composition and health effects is a continued challenge.…”

Impact of biodiesel on regulated and unregulated emissions, and redox and proinflammatory properties of PM emitted from heavy-duty vehicles

“…Grigoratos et al (2014) showed higher oxidative activity with increasing biodiesel blending when testing two light-duty vehicles with and without a DPF over the NEDC and Artemis cycles. Other studies have also demonstrated increases in oxidative activity with biodiesel blends (Cheung et al, 2009;Godoi et al, 2016;Guarieiro et al, 2014).…”

Effect of biodiesel fuel on “real-world”, nonroad heavy duty diesel engine particulate matter emissions, composition and cytotoxicity

“…Finally, metals composition could also contribute to the negative health impacts associated with diesel and biodiesel PM. Previous studies show that metals, particularly transition metals such as Cu, are a major component of diesel and biodiesel PM (Betha and Balasubramanian, 2011;Traviss et al, 2014;Godoi et al, 2016). The presence of transition metals, and polar and nonpolar organic species in biodiesel and diesel PM can induce production of Reactive Oxygen Species (ROS) in vitro (Verma et al, 2010;Hemmingsen et al, 2011;Fukagawa et al, 2013;Godoi et al, 2016).…”

“…Previous studies show that metals, particularly transition metals such as Cu, are a major component of diesel and biodiesel PM (Betha and Balasubramanian, 2011;Traviss et al, 2014;Godoi et al, 2016). The presence of transition metals, and polar and nonpolar organic species in biodiesel and diesel PM can induce production of Reactive Oxygen Species (ROS) in vitro (Verma et al, 2010;Hemmingsen et al, 2011;Fukagawa et al, 2013;Godoi et al, 2016). While ROS is integral to many cellular processes, increased exposure to ROS causes damage to intracellular components like DNA, lipids and proteins (Dröge, 2002).…”