Soluble Organic Fraction Research Articles

Insight into the mechanism of solution organic fractions on soot oxidation activity enhancement

The particulate matter and soluble organic fraction emitted by diesel engine are hazardous to environment and human health. Exploring the effect mechanism of soluble organic fraction on soot oxidation is beneficial for reducing the emissions. In this study, the effects of four different types of soluble organic fractions on the soot oxidation activity and physicochemical properties are investigated. The results show that the attachment of oxygen-containing soluble organic fractions enhances the soot oxidation and reduces the peak characteristic temperature. However, the low volatility soluble organic fractions without oxygen element inhibit soot oxidation. Additionally, the high volatility soluble organic fractions without oxygen element elicit limited effects on soot oxidation. the contents of aliphatic C-H functional groups, carbonyl CO functional groups, and carboxylic acid O-CO functional groups significantly increase after adding oxygen-containing soluble organic fractions, while the limited increase in functional groups is observed in soluble organic fractions without oxygen element. Solid soluble organic fractions adhere to soot particles in the form of small particles, leading a reduction in the initial particle size distribution, while liquid soluble organic fractions exhibit block and chain shapes around the soot particles, which makes the initial particle size distribution increasing. Moreover, the attachment of all soluble organic fractions disrupts the surface order of soot particle, leading to a decrease in soot graphitization. This study is beneficial for revealing the interaction mechanism between soot and soluble organic fractions.

Effect soluble organic fraction mass fraction on emission characteristics of carbon black

AbstractAccording to China's latest emission regulations for the year 2021, diesel vehicles are required to be equipped with a diesel particulate filter (DPF) in accordance with emission standards. To comprehensively understand the regeneration and emission performance of the DPF, an externally heated regeneration performance test bench was established. This study aims to investigate the influence of the soluble organic fraction (SOF) and types of carbon black on particle emissions from the outlet of the DPF. The experimental results indicate that both SOF and carbon black structure can affect DPF regeneration. When the SOF mass fraction increases to 20%, SOF plays a dominant role. The regeneration efficiency of Printex‐U and FW200 carbon black is 62.4% and 60.6%, respectively, with total mass concentrations of 21.8 and 14.9 mg/m3 at the DPF outlet. Compared to conditions without SOF, the regeneration efficiency and total mass concentration at the DPF outlet increase by 1.3 times and 6.6 times for Printex‐U carbon black, and 1.8 times and 440 times for FW200 carbon black, respectively. Additionally, when SOF mass fraction is 0%, the highest proportion of the average particle diameter for both Printex‐U and FW200 carbon black is in the [10, 20] nm range, at 20% and 95%, respectively. When the SOF mass fraction is increased to 20%, the proportions of the average particle diameter for both types of carbon black in the [10, 20] nm range rise to above 99%. This study provides a relevant experimental foundation for the emission control of DPF.

Antiherpetic Activity of a Root Exudate from Solanum lycopersicum.

The rise of drug resistance to antivirals poses a significant global concern for public health; therefore, there is a pressing need to identify novel compounds that can effectively counteract strains resistant to current antiviral treatments. In light of this, researchers have been exploring new approaches, including the investigation of natural compounds as alternative sources for developing potent antiviral therapies. Thus, this work aimed to evaluate the antiviral properties of the organic-soluble fraction of a root exudate derived from the tomato plant Solanum lycopersicum in the context of herpesvirus infections. Our findings demonstrated that a root exudate from Solanum lycopersicum exhibits remarkable efficacy against prominent members of the family Herpesviridae, specifically herpes simplex virus type 1 (HSV-1) (EC50 25.57 µg/mL, SI > 15.64) and human cytomegalovirus (HCMV) (EC50 9.17 µg/mL, SI 32.28) by inhibiting a molecular event during the herpesvirus replication phase. Moreover, the phytochemical fingerprint of the Solanum lycopersicum root exudate was characterized through mass spectrometry. Overall, these data have unveiled a novel natural product with antiherpetic activity, presenting a promising and valuable alternative to existing drugs.

Evaluation of Municipal Waste Compost in Relation to the Environmental Retention of Heavy Metals

This study investigates the performance of municipal compost as a heavy metal adsorbent for environmental protection systems. The performed assays test the effects of the pH (2–9) and contact time (5–250 min) on metal retention. To simulate leaching in natural systems, the soluble organic fraction was removed, leading to variations in the surface properties, including a 10% increase in the cation exchange capacity (CEC) and a 242% increase in the BET-specific surface area, accompanied by a small decrease in the surface charge (characterized by a less negative zeta potential values) of the washed municipal compost (WMC). Notably, these variations, which have not been found in previous research, yielded improved retention of Cu(II) and Zn(II) compared to raw municipal compost (RMC), attaining 96% retention for Cu(II) and 97% retention for Zn(II) at a pH of approximately 6.8–7.2 for a contact time of 120 min. The vast availability, cost-effectiveness, and resistance to desorption make municipal compost a viable option in a circular economy context for mitigating metal pollution across various environmental conditions. It is worth noting that this study can serve as a proxy for the expected outcomes in long-term exposure to environmental protection systems, enhancing the practical relevance of using compost for metal retention purposes.

Asphaltene-Derived Graphene Quantum Dots for Controllable Coatings on Glass, Fabrics, and Aerogels.

Graphene quantum dots (GQDs) derived from natural asphaltene byproducts can produce controlled hydrophobic or hydrophilic interfaces on glass, fabrics, and aerogels. A set of facile solvent extraction methods were used to isolate and chemically prepare materials with different surface functionalities from a commercially derived asphaltene precursor. The organic-soluble fraction was used to create hydrophobic and water-repellent surfaces on glass and cotton fabrics. The GQD solutions could also penetrate the pores of a silica aerogel, rendering it hydrophobic. Alternatively, by extracting the more polar fraction of the GQDs and oxidizing their surfaces, we also demonstrate strongly hydrophilic coatings. This work shows that naturally abundant GQD-containing materials can produce interfaces with the desired wettability properties through a straightforward tuning of the solvent extraction procedure. Owing to their natural abundance, low toxicity, and strong fluorescence, asphaltene-derived GQDs could thus be applied, in bulk, toward a wide range of tunable surface coatings. This approach, moreover, uses an important large-scale hydrocarbon waste material, thereby offering a sustainable alternative to the disposal of asphaltene wastes.

Determination of policyclic aromatic compounds, (PAH, nitro-PAH and oxy-PAH) in soot collected from a diesel engine operating with different fuels

A qualitative and quantitative analysis of polycyclic aromatic compounds (PACs; polycyclic aromatic hydrocarbons (PAHs), oxygenated and nitrated polycyclic aromatic hydrocarbons (OPAHs and NPAHs)) present in the soluble organic fraction (SOF) of different soot samples has been carried out to determine the effect of soot-generation conditions on their composition and health effects. The soot samples were generated using a diesel engine bench powered by diesel (DS) and biodiesel (BS) fuels under different combustion conditions. To optimize the procedure, a surrogate soot (Printex-U) and a certified reference material (SRM1650b) were also tested. Different extraction methods were used to extract the PAHs, OPAHs and NPAHs, and the Soxhlet technique using pyridine:acetic acid 1 % was found to be the most suitable procedure to extract the highest concentration (ng mg−1) and more types of PAHs and OPAHs from the soot. The results show that the PACs identified, and their concentrations, depend on the formation and collection conditions. The predominant compounds in all soot samples studied were fluorene (Flo), phenanthrene (Phe), fluoranthene (Fla), pyrene (Pyr), 9-fluorenone (9Flo) and 9,10-anthraquinone (9,10Anq). As such, the presence of these PACs in the atmosphere of urban and rural areas can mainly be attributed to the emissions from diesel vehicles. The percentage of OPAHs with respect to total PACs was highest in the soot generated from a biofuel. These oxidized compounds favor regeneration of the diesel particulate filter (DPF). The results also indicate that the carcinogenicity of the soot depends on the combustion conditions and type of fuel.

Effects of thermal and enzymatic pre-treatments on the solubilisation of extracellular polymeric substances (EPS) and subsequent anaerobic digestion of microalgae-bacterial biomass

Microalgae-bacteria biomass was digested through anaerobic digestion (AD) to produce biogas. Since microalgae typically have a more resistant cell wall than activated sludge (AS), its anaerobic biodegradability is limited. Therefore, three different pre-treatment techniques were evaluated for their effect on anaerobic biodegradability, especially of the extracellular polymeric substances (EPS). Firstly, heat at 70 °C for 1.5 h. Secondly, exposure to a mixture of commercially available enzymes (cellulase, α-amylase and protease), and thirdly, adding crude hydrolytic enzymes extracted by ultrasonication from a highly loaded anaerobic digestion cascade reactor. The first and third treatments had better effects than enzymatic pre-treatment with commercial enzymes, improving anaerobic biodegradability, the solubilisation of organic matter and increasing the methane production rate by 78 and 21 %, respectively. The EPS content of microalgae-bacteria biomass was considerably lower than reported for WAS, and about 40–50 % of the EPS consisted of proteins and polysaccharides. The hydrolysis of proteins and polysaccharides was quantified, and its effect on AD was discussed. A COD balance showed that the increase of soluble COD is due to the conversion of tightly bound EPS into loosely bound and soluble EPS but also due to the release of organic matter from cellular material. Although all pre-treatments increased the soluble organic fractions, especially those corresponding to EPS, none significantly improved the overall methane yield. Nevertheless, the methane production rate increased after thermal and pre-treatment with hydrolytic enzymes, which could result in smaller and more efficient anaerobic reactors.

Catalytic hydrothermal deoxygenation of sugarcane bagasse for energy dense bio-oil and aqueous fraction acidogenesis for biohydrogen production

The study focuses on the effective conversion of sugarcane bagasse (SCB) by catalytic deoxygenation using various alkali and metal-based catalysts under N2 pressure employing water as solvent. The specific influence of catalyst over bio-crude yields (bio-oil and aqueous fraction) including energy recovery ratio was explored. The optimum catalytic condition (Ru/C) resulted in ∼ 70% of bio-crude and 28% of bio-oil with an improved HHV (31.6 MJ/kg) having 11.6% of aliphatic/aromatic hydrocarbons (C10–C20) which can be further upgraded to drop-in fuels. The biocrude composed of 44% of aqueous soluble organic fraction (HTL-AF). Further, the carbon-rich HTL-AF was valorized through acidogenic fermentation to yield biohydrogen (Bio-H2). The maximum bio-H2 production of 201 mL/g of TOC conversion (K2CO3 catalyst) was observed with 7.7 g/L of VFA. The SCB was valorized in a biorefinery design with the production of fuels and chemical intermediates in a circular chemistry approach.

Cluster Analysis of Soluble Organic Fractions in Two Low-Rank Coals

A brief overview of the composition and structure of soluble organic compounds as well as organic macromolecules in coal is sufficient to support the development of the coal chemical industry and realize the clean, effective, and high value-added exploitation of coal. In this study, 14 groups of extracts were analyzed by a gas chromatograph-mass spectrometer; seven stages of solvent-graded extraction were carried out on two typical low-rank coals, and the extracted substance spectrum data were processed by principal component analysis and cluster analysis to investigate the molecular makeup and structure of the soluble organic compounds in the two coals. CS2 had a better extraction effect on aromatic hydrocarbons, and methanol was better for the enrichment and separation of oxygenated compounds. Hexane and petroleum ethers have a good extraction effect for aliphatic hydrocarbons; benzene has a good effect for the extraction of nitrogenous compounds; acetone has a greater extraction rate for alcohols; tetrahydrofuran has a more obvious extraction effect for ketones; the mixed solvent of tetrahydrofuran and methanol has a greater extraction rate for esters.

Simulated soot oxidation in the presence of catalyst and soluble organic fraction using thermogravimetric analysis

Simulated soot oxidation in the presence of catalyst and soluble organic fraction using thermogravimetric analysis

Review of morphological and chemical characteristics of particulates from compression ignition engines

Particulates from compression ignition (CI) engines have received serious attention in the last two decades. CI engines emit higher particulate matter (PM) and nitrogen oxides (NOx) than spark ignition (SI) engines. Both these species are harmful to human health and the environment. Compared to NOx emissions, PM constitutes many more chemical species in solid and liquid phases. This review paper focuses on soot morphology and chemical characterization of PM emissions from CI engines. Effects of different fuels, lubricating oil, and engine operating conditions on particulate characteristics are analyzed exhaustively. The first part of this paper focuses on the effects of particulates on living organisms, the consequences of exposure to diesel particulates, and the composition of diesel particulates. In recent decades, micro and nano-scale characteristics of PM have been exhaustively investigated to understand its structure, formation, and chemical functionalities. Typically, particulates comprise of elemental carbon (EC), organic carbon (OC), polycyclic aromatic hydrocarbons (PAHs), the soluble organic fraction (SOF), and trace metals. This paper summarizes most aspects of diesel particulate emissions for the benefit of active researchers in the field and underlines the importance of particulate emission reduction from the CI engines. Diesel combustion generates particles with enormous long-chain aggregates of smaller sizes and immature soot particles. Low-temperature combustion (LTC) modes and oxygenated fuels reduce the soot emissions and generate compact/clustered aggregates. Oxygenated fuels in CI engines produce more nucleation mode particles (NMPs) and high-reactivity soot aggregates. Higher trace metal concentrations were observed in diesel origin particulates than biofuel origin particulates. Biodiesel origin particulates possess higher mutagenicity and carcinogenicity because of nitro-PAHs. Transient engine operations cause higher particulates than steady-state engine operations.

Trace and Rare Earth Element Partitioning in Organic Fractions of Mudstones during the Oil Formation

In order to investigate trace and rare earth element partitioning in organic fractions of mudstones, this study isolated organic fractions of mudstones, including insoluble organic fraction (kerogen), soluble organic fraction (extract), or expelled hydrocarbon (reservoir solid bitumen), and the isolated organic fractions and their corresponding whole rocks for trace and rare earth element compositions were measured. Analysis of trace and rare earth element compositions in organic fractions of lacustrine and marine mudstones revealed that mudstone kerogens were more enriched in rare earth elements (REE) and redox-sensitive trace elements (e.g., U, Mo, and Ni) relative to corresponding whole rocks. During the oil generation, middle rare earth elements (Sm-Ho), especially Eu, migrated from kerogen to extract more easily than the rest REE. The Eu was easily transferred to soluble hydrocarbon under the acidic and reducing environments formed by oil generation, resulting in the higher concentrations of Eu relative to its neighboring REE (Sm and Gd) and the pronounced positive Eu anomalies. Transition metal elements (e.g., Mo, V, Cr, Co, Ni, Cu, and Zn) also more easily released from kerogen than the rest elements, especially V and Ni. The enrichment and mobilization of trace elements in organic fractions of mudstones, such as Mo, U, V, Ni, and Ba, are closely related with their geochemical behaviors during the depositional and early digenetic processes, providing the potential information for predicting the distribution characteristics of trace elements in the expelled hydrocarbons of mudstones (e.g., crude oil and solid bitumen) and fingerprinting of oil to source.

Biological toxicity risk assessment of two potential neutral carbon diesel fuel substitutes

We investigated the biological response of soluble organic fraction (SOF) and water-soluble fraction (WSF) extracted from particulate matter (PM) emitted by an automotive diesel engine operating in a representative urban driving condition. The engine was fueled with ultra-low sulfur diesel (ULSD), and its binary blends by volume with 13% of butanol (Bu13), and with hydrotreated vegetable oil (HVO) at 13% (HVO13) and 20% (HVO20). Cytotoxicity, genotoxicity, oxidative DNA damage and ecotoxicity tests were carried out, and 16 polycyclic aromatic hydrocarbons (PAH) expressed as tbenzo(a)pyrene total toxicity equivalent (BaP-TEQ) were also analyzed. The Hepatocarcinoma epithelial cell line (HepG2) was exposed to SOF for 24 h and analyzed using comet assay, with the inclusion of formamidopyrimidine DNA glycosylase (FPG) and endonuclease III (Endo III) to recognize oxidized DNA bases. The WSF was evaluated through acute ecotoxicity tests with the aquatic microcrustacean Daphnia pulex (D. Pulex). Results showed that there was no cytotoxic activity for all tested SOF concentrations. Genotoxic responses by all the SOF samples were at same level, except for the HVO13 which was weaker in the absence of the enzymes. The addition of the FPG and Endo III enzymes resulted in a significant increase in the comet tail, indicating that the DNA damage from SOF for all tested fuel blends involves oxidative damage including a higher level of oxidized purines for ULSD and Bu13 in comparison with HVO blends, but the oxidized pyrimidines for HVO blends were slightly higher compared to Bu13. The WSF did not show acute ecotoxicity for any of the fuels. Unlike other samples, Bu13-derived particles significantly increase the BaP-TEQ. The contribution to the genotoxic activity and oxidative DNA from SOF was not correlated to BaP-TEQ, which means that the biological activity of PM might be affected also by other toxic compounds present in particulate phase.

Descriptive and inferential statistics as an exhaust emission comparative tool between different engine operating conditions and fuels. Application to highly oxidized biodiesel blended with primary alcohols

Despite the great electrification that vehicle fleet is expecting in the coming years, internal combustion engines still play an important role in the transport sector. New regulations for polluting emission reduction and economy decarbonization, together with lower availability of fuels from non-renewable sources, have led to the search of renewable non-polluting fuels. This is a fundamental research sector in the next decades. Biodiesel, with a long history, has proven to be a good candidate. However, diversification will be the key to success in terms of sustainable mobility, avoiding negative dependency in the future. In this context, discarded oil is key to both produce an economically affordable biodiesel and to valorize this residue. This research studies the possibility of using a binary mix of fuels, including primary alcohols (propanol and pentanol), at 10 and 20% v/v, with highly-oxidized dumped oil biodiesel. These mixtures have been tested in a diesel engine running at 1300, 1700 and 2400 rpm, under 25% and 46% engine load for each rotational speed. To check the significance and reproducibility of obtained data, polluting emissions and engine input parameters have been evaluated through descriptive and inferential statistics. Results indicate that 20% 1-propanol/biodiesel blend allows mitigating the increase in fuel consumption of biodiesel compared to fossil diesel fuel. Moreover, overall soluble organic fraction (SOF) and unburned hydrocarbon emissions are lower for biodiesel and its blends than for diesel fuel. Furthermore, the combination of the use of 10% propanol and maximum EGR valve opening can achieve a significant reduction of NOx emissions. As a final conclusion, the proposed statistical study has shown to be a reliable tool to compare emissions and input parameters from different tests, especially under intra-urban conditions. This overcomes the large data variability from emission tests.

Effect of nonthermal plasma with different ozone concentrations on the oxidation and removal of different components in particulate matter

Nonthermal plasma (NTP) technology can oxidize and decompose diesel particulate matter (PM) under much lower temperatures (≤200 °C) without catalyst, showing promise for potential applications. A self-made NTP generator was used to produce NTP gas that reacted with PM at a certain reaction temperature and reaction time, and the concentration of O3 in NTP was modified by adjusting the working parameters. Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and gas chromatography-mass spectrometry (GC-MS) were used to analyze changes in the surface functional groups, component oxidation activity, removal effect, and the soluble organic fraction (SOF) of PM samples before and after processing. As the O3 concentration increased, the effect of NTP on PM removal strengthened. PM surface functional groups can be converted from C–OH into CO under the action of NTP at high O3 concentrations. The oxidation activity of the volatile fraction (VF) and soot in PM can be substantially improved under high O3 concentrations. Higher O3 concentrations resulted in increases in the number of oxygen-containing groups in the molecular formula of SOF and the ratio of components. This study provide a certain reference value for the strategy of removing PM pollutants from diesel engines and even the atmosphere.

Ablation Rates of Organic Compounds in Cosmic Dust and Resulting Changes in Mechanical Properties During Atmospheric Entry

AbstractA new experimental system is described for studying the pyrolysis of the refractory organic constituents in cosmic dust during atmospheric entry. The pyrolysis kinetics of meteoritic fragments (CM2 and CV3 carbonaceous chondrites, radius = 36–100 μm) were measured by mass spectrometric detection of CO2 and SO2 at temperatures between 625 and 1300 K, with most carbon being lost between 700 and 800 K. The complex time‐resolved kinetic behavior is consistent with two organic components—one significantly more refractory than the other, which probably correspond to the insoluble and soluble organic fractions, respectively. The measured temperature‐dependent pyrolysis rates were then incorporated into the Leeds Chemical Ablation Model, which demonstrates that organic pyrolysis should be detectable using a high performance/large aperture radar. Atomic force microscopy was used to show that although the residual meteoritic particles became more brittle after organic pyrolysis, they also became slightly harder, withstanding stresses that are at least three orders of magnitude higher than would be encountered during atmospheric entry. This suggests that most cosmic dust particles (radius <100 μm) will not fragment during entry into the atmosphere as a result of organic pyrolysis, although a subset of slow‐moving, low density particles mostly from Jupiter‐family comets could fragment.

New insights of anaerobic performance, antibiotic resistance gene removal, microbial community structure: applying graphite-based materials in wet anaerobic digestion

ABSTRACT The addition of carbonaceous materials into anaerobic digestion (AD) has gained widespread attention due to their significant effects on anaerobic performance and antibiotic resistance gene (ARG) removal. This study selected graphite, graphene, and graphene oxide (GO) as additives to investigate variations in AD performance, ARG removal, microbial community diversity and structure in wet AD systems. The results indicated that the addition of graphite-based materials in wet AD systems could increase degradation of solid organic matters by 0.91%-3.41% and utilization of soluble organic fractions by 10.43%-13.67%, but could not stimulate methane production. After the addition of graphite and graphene, ARG removal rates were effectively increased to 90.85% and 94.22%, respectively. However, the total ARG removal rate was reduced to 77.46% with the addition of GO. In addition, the microbial diversity in the wet AD process was enhanced with the addition of GO only, graphite and graphene led to a reduction in it. As for bacterial community, graphite and graphene increased the abundance of Thermotogae from 43.43% to 57.42% and 58.74%, while GO increased the abundance of Firmicute from 49.90% to 56.27%. For the archaeal community, the proportion of hydrogenotrophic methanogens was improved when adding each graphite-based material; however, only GO increased Methanosaeta that was acetoclastic methanogens. Finally, methanogens were found as the ARG host, and ARGs that belong to the same subtype might exist in the same host bacteria.

Evolution of particulate matter deposited in the DPF channel during low-temperature regeneration by non-thermal plasma

In this paper, diesel particulate filters (DPFs) were regenerated at a low temperature (100 °C) using a non-thermal plasma (NTP) injection system. The physical and chemical characteristics of the particles deposited at different regeneration stages, such as their macromorphology, microstructure, oxidation activity, surface functional groups, and soluble organic fraction, were analyzed. The results showed that when NTP flowed through the DPF, the deposited particles were oxidized, decomposed, and then removed from the channels. The soot cake dispersed into blocks from an initially dense morphology and gradually shrank until it disappeared. The residual ash lost the initial spherical structure of the carbonaceous particulate matter (PM). The weak part of the flocculant structure of PM broke first during the oxidation of NTP active substances and decomposed into a chain structure. As DPF regeneration proceeded, O atoms were continuously bonded into the PM to form oxidation intermediate products that contained C-O, C=O, and other functional groups, which improved the PM oxidation activity. Changes in the physical and chemical properties of PM at the DPF regeneration interface were more significant than those at the most downstream sampling position. The high carbon atom fraction in the soluble organic fraction (SOF) decreased, and the DPF regeneration by NTP involved the continuous removal of carbon atoms.

Dynamic modeling of a full-scale membrane bioreactor performance for landfill leachate treatment.

Leachate treatment is crucial in landfill management. As landfill ages, inert constituents and ammonia nitrogen concentration in leachate increases, which results in a decrease in biological treatability. In this study, a full-scale MBR treating leachate was dynamically modeled using ASM1. The investigated landfill has been serving for more than 25years; thus, a decrease in biodegradable organic content and an increase in nitrogen content of the leachate is expected in the years ahead. The calibrated model predicted MLSS, effluent COD, and effluent TN concentrations with high accuracy. Following the calibration study, it was found that soluble inert COD and soluble inert organic nitrogen fractions were the primary reasons ofhigh COD and TKN concentrations in the effluent, respectively. The validated model of the full-scale MBR system treating leachate can be a useful tool to understand the limitations of the system. Soluble inert constituents of the leachatethat pass through the membranenecessiate additional treatment processesfor discharge into surface water bodies.

Comparative study on combustion and particulate emissions for diesel-biodiesel and diesel-diglyme blends

Experiments were conducted on a 4-cylinder direct-injection diesel engine using ultralow sulfur diesel blended with biodiesel or diglyme to investigate the influence on combustion and particulate emission characteristics. Five biodiesel blends and five diglyme blends with oxygen concentrations of 2%, 4%, 6%, 8% and 10% were prepared respectively and tested separately at five engine loads of maximum torque speed of 2400 rpm with same boundary condition. With the increase of oxygen content, in-cylinder pressure and heat release curve advanced for both blends but the peak values were lower than of diesel, the trend was more obvious for diglyme blends. Besides combustion centre was slightly varied for biodiesel fuels but postponed significantly for diglyme blends. Meanwhile, smoke opacity, brake specific particulate emissions and the geometric mean diameter of particle decreased accompanying with the increase in soluble organic fraction proportion, and biodiesel blends had more obvious variations. In addition, the total particle number concentration and the particle smaller than 100 nm in diameter increased gradually and unidirectionally for biodiesel blended fuels, but for diglyme blends, the peak value of the total particle was found from the blend containing 2% oxygen and the particles from all diglyme blends were higher than that from diesel. Compared with biodiesel, diglyme fuels had more particulate and particles emissions on the same oxygen base.