Sunflower Oil Biodiesel Research Articles

Applied AMT machine learning and multi-objective optimization for enhanced performance and reduced environmental impact of sunflower oil biodiesel in compression ignition engine

Biodiesel has emerged as a compelling substitute for conventional diesel fuel, providing a sustainable and eco-friendly choice for fueling compression ignition engines. This comprehensive study investigates the influence of biodiesel, specifically derived from sunflower oil, through the esterification method, on crucial engine performance parameters and environmental effects. The study examines the impact of varying engine torque on the performance of a single-cylinder, four-stroke compression ignition engine, encompassing parameters such as brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC), as well as exhaust emissions, including unburned hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx). Four distinct biodiesel blends (B10, B20, B30, B40) with varying sunflower oil content are systematically compared to pure diesel (B0). The engine operates at a consistent speed of 1700 rpm, while the torque undergoes controlled adjustments from 0 to 10 Nm. Subsequently, this study explores the application of an alternating model tree (AMT) machine learning algorithm to establish relationships between independent factors, specifically torque and biodiesel volume (%vol), and dependent variables, including BTE, BSFC, CO, and NOx in a combustion engine. Additionally, the study employs a multi-objective ameliorative whale optimization algorithm (AWOA) to optimize the model's output. The objective is to identify optimal values for torque and%vol that maximize engine performance (BTE) while minimizing engine emissions (CO and NOx) and reducing fuel consumption (BSFC). The optimization process yields noteworthy results, with AWOA achieving peak BTE at 29.714 %, BSFC at 0.262 kg.kWh-1, and NOx emissions at 992 ppm at torque 7.3 N.m and 13% vol. In contrast, particle swarm optimization (PSO) secured the minimum CO level at 0.123 %, with torque set at 7.6 N.m and 26% vol. The AMT models demonstrate high prediction accuracy, with coefficient of determination (R2) values exceeding 0.98.

Performance comparison of empirical model and Particle Swarm Optimization & its boiling point prediction models for waste sunflower oil biodiesel

The absence of correlations for predicting the boiling point of biodiesels prevents fuel users to achieve effective engine performance. Among the quality regulator of rudimentary fuel properties is the boiling point and its absence in literature is preventing fuel handlers to achieve actual engine performance. In this study, the mechanism of sunflower oil methanolysis was investigated by Response Surface Methodology (RSM) and Particle Swarm Optimization (PSO). The empirical model (EM) was utilized to correlate the optimal yield and trans -esterification variables for methylic biodiesel production. Thereafter, statistical regression techniques were employed to model the MBP of biodiesel vs. biodiesel fraction and MBP of biodiesel vs. kinematic viscosity. The yield of waste sunflower oil methyl ester (WSOME) (97%) was the uppermost at the methanol/SFO molar ratio of optimal of 6/1, KOH of 1 %wt, and retention time of 78 min. The PSO model exhibited an advanced coefficient of determination, and an inferior value of root mean squared errors related to the RSM model. PSO predicted values, as related to RSM predicted yield shows its dependability and expediency for prediction deprived of conservative experimentation. The fuel properties of the WSOME synthesized were within the ranges of established green fuel standards. The RSM with PSO has been exhibited efficient tools for exploring the methylic biodiesel production from WSO. Least square regression and parabolic equation correlated MBP as a function of bio-diesel fraction and MBP as a function of kinematic viscosity. In conclusion, the results of this study can be useful for biodiesel production from industrial waste oil and the prediction of MBP in the biodiesel industry.

Experimental and empirical analysis of a diesel engine fuelled with ternary blends of diesel, waste cooking sunflower oil biodiesel and diethyl ether

The present study was aimed to evaluate the performance, combustion, and emission characteristics of a single-cylinder diesel engine fuelled with ternary blends of diesel, WCSO biodiesel and DEE. The preliminary results with diesel – WCSO biodiesel blends revealed that B20 is an optimum blend as its engine characteristics were closer to that of diesel. In order to increase the biofuel concentration in the blend without any compromise in the engine characteristics, B20 was blended with DEE at proportions of 5%, 10%, and 15% by volumetrically displacing the diesel concentration in the blend. For 10% addition of DEE in B20, the cetane index improved by 2.8% and the viscosity reduced by 29%. The improved fuel properties resulted in higher peak in-cylinder pressure, shorter ignition delay, and reduced combustion duration for DEE10. The BSFC reduced by 3.2% and BTE increased by 1.3% for DEE10 when compared to B20 at full load condition. Though the ternary blends significantly reduced CO, NOX and smoke emissions, an increase in HC emission was observed. In comparison with diesel, CO and smoke emissions decreased by 49.9% and 3.6%, respectively, for DEE10 at full load condition. The results showed that the optimum ternary blend, DEE10, can be used as a drop-in-fuel in an unmodified diesel engine. Further, an ANN model was developed, tested and validated with the engine characteristics of binary and ternary blends. The developed model precisely predicted the engine characteristics of different test fuels with a higher R2 (0.98) value. The developed ANN model is further used to find the optimum DEE concentration for B40 and B60 blend.

Engine performance and PM concentrations from the combustion of Iraqi sunflower oil biodiesel under variable diesel engine operating conditions

The most desirable alternative fuels are biodiesel among several of alternative fuels to use in diesel engines. The biodiesel used in this study is sunflowers oil which derived from local renewable sources. Also, biodiesel considered a best alternative to conventional diesel because it clean and environment friendly. The experimental results shown that the biodiesel blends (B20, B50, and B100) increased the brake specific fuel consumption (BSFC) compared with pure diesel fuel. According to the results, it is indicated that the biodiesel blends reduced the brake thermal efficiency (BTE) and exhaust gas temperatures (EGT) during the combustion of B20, B50, and B100 for all engine operating conditions. The exhaust gas temperature and BSFC increased with increase the operating conditions of engine loads and speeds. The data indicated that PM concentrations reduced with biodiesel blends combustion compared with diesel under variable engine loads and speeds. Besides that the concentrations of PM reduced by 16.847, 28, and 43.34% combustion of B20, B50, and B100, when compared with petroleum diesel under the same conditions of engine loads and speeds. The results give insight that the oxygen content in the biodiesel has favourable effect on reducing the PM concentrations.

Effect of acetone as an oxygenated additive with used sunflower oil biodiesel on performance, combustion and emission in diesel engine

ABSTRACT A major problem that is confronting mankind is the rapid depletion of fossil resources creating an energy demand along with their environmental impact. Therefore, finding an alternate energy source is the primary goal to attain sustainable development. Biodiesel is a promising alternate energy source for compression ignition engines. But it has some drawbacks like lower thermal efficiency, higher emission of smoke, NOx, CO and HC. Adding fuel additives with biodiesel–diesel blends is a fruitful method to overcome these problems. In this work, acetone is used as an oxygenated fuel additive in the volumetric proportion of 5%, 10%, and 15% with biodiesel–diesel blend and named as B20A5, B20A10 and B20A15. The performance, combustion, and emission characteristics of single-cylinder, four-stroke, water-cooled vertical diesel engine has been evaluated. The experimental results revealed that B20A15 has resulted in a nominal increase in brake specific fuel consumption by 8%, brake thermal efficiency of 1%, and reduction in CO by 18.4%, smoke opacity by 4.46%, HC by 1.42%, and NOx by 4.36% when compared to diesel at full load condition.

Combustion Performance Sunflower Oil Biodiesel on Liquid Fuel Burner

The current study investigated the combustion performance of sunflower oil-based biodiesel fuel blends with diesel at the ratio of B10 (10% biodiesel, 90% diesel), B15 (15% biodiesel, 85% diesel), B25 (25% biodiesel, 75% diesel) and B50 (50% biodiesel, 50% diesel). The combustion performance of this fuel is evaluated based on the value of the combustion chamber wall temperature, the thermal efficiency of the burner as well as the concentration of emission gases released such as nitrogen oxides (NOx), sulfur dioxide (SO?), and carbon monoxide (CO). Sunflower oil-based biodiesel blend fuel was measured and compared to diesel. All fuels tested were burned using a combustion chamber with one of its ends open, at five different equivalence ratios, namely, fuel-lean condition (? = 0.8 and 0.9), stoichiometry (? = 1.0), and fuel-rich (? = 1.1 and 1.2). The results show that sunflower oil-based biodiesel fuels burn at lower temperatures. This results in lower fuel thermal energy, and thus, lower thermal efficiency of the burner compared to diesel. Moreover, the emissions produced are lower (except for NOx) compared to diesel for all equivalence ratios. The results also show that the use of biodiesel is useful for different modern applications, especially in the industrial sector as it is more environmentally friendly and can be used as an alternative to petroleum fuels.

Synthesis of pyrogallol derivative as antioxidant additive for biodiesel using methyl linoleate from sunflower oil

Biodiesel is a renewable plant-based fuel as an alternative to fossil fuels containing fatty acid methyl esters. However, biodiesel has the disadvantage of oxidation instability because of the double bonds in the constituent fatty acid structures. One of the most effective antioxidant for biodiesel is pyrogallol. Unfortunately, pyrogallol has a low solubility in biodiesel. Subsequent research was developed by synthesizing pyrogallol derivative through the reaction between pyrogallol and a pure methyl linoleate using 2,2-diphenyl-1-picrylhydrazyl or DPPH as a catalyst. The results showed that the pyrogallol derivative formed was more soluble in biodiesel. However, the use of pure methyl linoleate is not economical because it has a high selling price. In this research, sunflower oil biodiesel with 54.13 % methyl linoleate which has been tested by GCMS will be used to synthesize pyrogallol derivative with a ratio of 10 mL biodiesel, 5 ml DPPH, and 5 mL pyrogallol. FTIR shows a shifting peak at 1240 cm−1 which shows the formation of pyrogallol derivative. LCMS-MS indicates a possible molecular weight at 634 m/z consisting of methyl linoleate and dimer pyrogallol. UV-Vis of the derivatives in biodiesel shows that the derivative is more soluble in biodiesel in comparison with the solubility of pure pyrogallol.

The Potential of Pd/CX100 to Use as Anode in a Paper-Based Microfluidic Fuel Cell for the Oxidation of Crude Glycerol Samples

In this paper is reported the energy generated in a paper-based microfluidic fuel cell (paper-based mFC) using Pd/CX100 as anode and glycerol from three sources: reagent grade glycerol, crude glycerol from sunflower oil biodiesel, and crude glycerol from used cooking oil biodiesel, as fuels. TEM, SEM, XRD, XPS, and cyclic voltammetry were employed for the Pd/CX100 characterization. The paper-based mFC using Pd/CX100 as anode was evaluated employing 0.1 M and 0.5 M glycerol of each glycerol sample and achieving power densities of 0.242 and 0.160; 0.15 and 0.127; and 0.108 and 0.090 mW cm-2 for reagent grade glycerol, glycerol from sunflower oil biodiesel, and glycerol from used cooking oil biodiesel, respectively.

Techno-economical and energy analysis of sunflower oil biodiesel synthesis assisted with waste ginger leaves derived catalysts

The present study was carried out to investigate biodiesel production via transesterification of sunflower oil employing heterogeneous catalyst derived from indigenous ginger (Zingiber Officinale) leaves. It also aims to compare the techno-economy performance of the ginger-based catalysts in 3 different forms viz. calcinated (CGL), activated by KOH (KGL) and NaOH (NGL). The plant-based catalysts were characterised by Scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) and Fourier transform infrared spectroscopy (FTIR). The parametric effects on the biodiesel production such as reaction time, methanol to oil ratio and catalyst loading were investigated. The experimental result shows that 1.6 wt % catalyst, 6:1 M ratio of alcohol to oil, 1 h 30 min of reaction time with a speed of 200 rpm gave the best results. It was found that the KGL obtained highest biodiesel yield of 93.83% under optimum conditions. Subsequently, the specific energy and energy productivity of KGL catalyst was found to be 1.2728, 26.1544 MJ/kg and 0.0382 kg/MJ, respectively, per 1 L of biodiesel. Meanwhile, the renewable energy to non-renewable energy ratio for CGL, KGL and NGL is found to be 3.17, 4.01 and 3.67, respectively. A higher sustainable renewable energy-yield ratio and overall economical profit cost ratio are preferable for the biodiesel production process.

Biodiesel feedstocks selection strategies based on economic, technical, and sustainable aspects

The interest in sustainable energy sources such as biodiesel is growing due to unpredictable fossil fuel prices, depletion of their origins, inconsistent supply, geopolitical instability, and conflicts of fuel/oil-producing countries, global politics, and sanctions. The selection of the right biodiesel feedstocks is the first step of mass biodiesel production. This paper is aimed at defining the best possible biodiesel feedstocks using various multiple criteria decision analysis (MCDA) processes. Several facets that can effect on the biodiesel feedstocks selection process are economic, technical, environmental, and social aspects. This study concentrated on fifteen ‘criteria’ based on the economic aspect (cost of biodiesel production), technical aspects (physicochemical properties and structural composition (fatty acid) of biodiesel feedstocks), and environmental aspects (sustainable land usage for crop production) for the selection process. Sixteen most popular biodiesel feedstocks, namely Palm, Soybean, Sunflower, Moringa, Jatropha, Pongamia, Mustard, Coconut, Tallow, Peanut, Corn, Cottonseed, Ricebran, Beauty leaf, Rapeseed and waste cooking oil biodiesel were investigated as ‘alternatives’ in this analysis. For ‘weight’ determination of each criterion, five weighting methods in percentage, namely EQUAL, CRITIC, ENTROPY, Analytical hierarchical process (AHP), and Fuzzy Analytical Hierarchical Process (FAHP) were used. Four MCDA processes, namely PROMETHEE Graphical Analysis for Interactive Assistance (GAIA), Weighted sum method (WSM), Weighted product method (WPM), and Technique for order preference by similarity to ideal solution (TOPSIS) were implemented for this investigation. The findings indicate that Coconut rated best and Soybean was regarded as the worst feedstock among those alternatives.

Experimental Study on Performance and Emission Characteristic of Diesel Engine using Sunflower oil Biodiesel Blends

Biodiesel fuel is a liquid biofuel produced by chemical process form new and used phytogenic oils, animal fats. Biodiesel fuels can be utilization alone or mixing with the pure diesel at different proportion. In the present work a diesel engine type (FIAT) , four cylinder, variable speed, direct injection was operated by sunflower oil methyl ester , biodiesel at different blend ratio . five different ratio of biodiesel blends 10%, 20%, 30%, 40%, and 50% by volume is used in this study and compared with using of pure diesel at variable loads and variable engine speed. The effect of biodiesel additive to pure diesel on the performance and emission characteristics. Adjust the engine speed at 1100 rpm by means of the engine tachometer and digital tachometer, and reduce the load gradually until the engine speed increased to 1900 rpm automatically by increments of 200 rpm. The BSFC for B20 It seems less than the other ratio of biodiesel blends, and the BTE of biodiesel blends is lower than the pure diesel but the B20 having high BTE in comparison with the other biodiesel- diesel mixtures. the UHC and CO emission for B20 is less than the biodiesel blends and pure diesel, but the NOX emission for B20 is lower than the other biodiesel blends and higher than pure diesel. The present work shows the B20 relatively is a better performance and combustion characteristic than that biodiesel blends ratio.

Biodiesel Blends Startability and Emissions During Cold, Warm and Hot Conditions

The time and emissions during cold starting were investigated at cold and hot temperatures (i. e., – 10°C, 0 °C, 25°C and 50 °C). The effect of injection timing (IT) on these factors was also studied at four ITs before top dead centre (BTDC) i. e., (12 , 15 , 20 and 23 BTDC). The results were compared with engine operation at 17 BTDC (factory IT). Sunflower vegetable oil and yellow grease were used as raw materials to prepare bio diesel fuels through transesterification. B20 (20% sunflower oil biodiesel+80% diesel) and W20 (20% yellow grease biodiesel+80% diesel), together with neat conventional Iraqi diesel fuel, were used to analyse engine startability and emissions under cold and hot starting conditions. Results indicated that adding biofuel affects the engine starting response and that the starting time stabilises at high starting temperatures. At a low starting temperature (i. e.,–10 °C), hydrocarbon (HC) and carbon monoxide (CO) concentrations increase significantly. At moderate and high starting temperatures, the oxygen content in the biofuel blend plays a dominant role in reducing the HC and CO concentrations. Smoke opacity has increased notably for the biodiesel blends at low starting temperatures but has decreased significantly at moderate and high starting temperatures. Both biofuel blends emit higher levels of nitrogen oxide than the neat diesel fuel. Noise increases at low starting temperatures, thereby indicating rough combustion.

Sunflower oil-based MCC surface modification to achieve improved thermomechanical properties of a polypropylene composite

A biobased approach was taken to endow microcrystalline cellulose (MCC) with surface hydrophobicity using sunflower oil biodiesel (sunflower oil fatty acid ethyl esters, SFEEs) and thereby improve the compatibility with a hydrophobic polypropylene (PP) matrix. This environmentally friendly green chemistry approach introduces a monomolecular long-chain fatty acid layer on the MCC surface, making the surface hydrophobic. However, as per the X-ray Diffraction results, this surface modification process had no effect on the crystal structure of MCC. The inclusion of surface-modified MCC in the PP matrix significantly improves the thermomechanical properties of the composite. The tensile, impact and hardness properties of the surface-treated fiber reinforcements were improved by 11%, 71%, and 23%, respectively, compared to those of nonreinforced PP. The thermal stability also was improved considerably by the incorporation of modified MCC into PP.

Performance Assessment of DI-Diesel Engine using the Blend of Sunflower Oil and Rice Bran Oil

Biodiesel, a derivative of vegetable oils and animal fats, is used nowadays as an alternative renewable and sustainable fossil fuel. In this work, the investigation of manufacture, characterization, and results of biodiesel blends are carried out using two important feedstock’s, sunflower oil and ricebran oil on engines. For the collective advantageous of sunflower oil and ricebran oil, the two biodiesels are combined together and the mixture is analysed to assess the engine performance and emission characteristics. NaOH catalyzed transesterification process is used for producing the Biodiesels A 4.4 kW, four-stroke, single-cylinder and direct fuel injection diesel engine is used for measuring physic-chemical with full load and varying speed conditions and using the specifications of ASTM D6751 standard, the properties are compared. It is observed that the Biodiesel mixtures produce a low brake torque and high brake-specific fuel consumption (BSFC) in addition to the reduction of CO and HC emissions. NOx, however, is reduced considerably with the improvement of brake thermal efficiency. The Performance analysis indicates that the mixture of sunflower oil and ricebran oil improves performance and emission characterizes over sunflower oil and ricebran oil biodiesel when they are unmixed..

Evaluation of Distribution of Succinic Acid between Binary Phase System with Biodiesel + N,N-Dioctyloctan-1-amine

The present study is aimed at using one of the most promising methods called reactive extraction to extract succinic acid from aqueous solution by using N,N-dioctyloctan-1-amine in biodiesel as diluent made from sunflower oil, rice bran oil, sesame oil, and karanji oil. The results of extraction studies with the diluents (physical) showed their inability to recover any acid by themselves. In reactive extraction, the organic phase extracting power solely depends on tri-n-octylamine. The ranges of the distribution coefficient are found as 7.62–18.12 for sunflower oil biodiesel, 8.33–17.45 for rice bran oil biodiesel, 7.0–17.67 for sesame oil biodiesel, and 9.85–21.36 for karanji oil biodiesel. The ranges of the loading ratio are 0.1–3.0 for sunflower oil biodiesel, 0.1–2.9 for rice bran oil biodiesel, 0.2–2.9 for sesame oil biodiesel, and 0.1–2.9 for karanji oil biodiesel. The karanji and sunflower oil showed higher values of distribution coefficient (KD) over rice bran oil and sesame oil which might be due to presence of both C20 and special fatty acids. The results show that biogenous diluents along with N,N-dioctyloctan-1-amine as extractant form a nontoxic and viable option for the extraction of succinic acid in the binary phase system.

Extractive Separation of Acetic Acid from Aqueous Solution using Tertiary Amine + Biodiesels at 298±K

The present paper deals with the removal of acetic acid from aqueous solution using Tri-n-octyl amine (TOA) as extractant in biodiesels synthesized from sunflower, sesame and rice bran. Batch extraction of acetic acid from aqueous solution was carried out and extraction efficiency and loading factors were calculated by varying initial acid concentration and the percentage of Tri-n-octyl amine (TOA) in biodiesels on volume/volume basis. For sunflower oil biodiesel system- the extraction efficiency lies between 57.74 (10% TOA)-77.14 (30% TOA), for sesame oil biodiesel system- the extraction efficiency lies between 53.31 (10% TOA)-79.79 (30% TOA) and for ricebran oil biodiesel system- the extraction efficiency lies between 58.10 (10% TOA)-76.50 (30% TOA). The results revealed that the combination of TOA and biodiesel is efficient for removing acetic acid from aqueous solution.

Comparison of engine characteristics with biodiesels produced from fresh and waste cooking oils

The research focus on alternative fuels has intensified and is gaining momentum owing to depleting crude oil reserves and the adverse environmental effects associated with the use of fossil fuels in automotive engines. In the present work, the feasibility of producing biodiesel from waste cooking oil (WCO) and utilizing it in a light-duty diesel engine is investigated. The composition and properties of biodiesel produced from restaurant waste sunflower oil are compared with those of fresh sunflower oil biodiesel, and the differences are found to be negligible. The effects of replacing fossil diesel with WCO biodiesel in comparison to fresh sunflower oil biodiesel are studied in a light-duty diesel engine under constant speed and varying load conditions. The results show that the use of WCO biodiesel increases brake specific fuel consumption by 22%, reduces carbon monoxide and smoke emissions by 6.3% and 69.2% respectively, and increases emission of oxides of nitrogen by 5.6%. Further, the engine characteristics are found to be almost the same between fresh and WCO biodiesels. Based on the results obtained, it is recommended to use WCO biodiesel as a potentially low-cost replacement for diesel in automotive engines to circumvent food versus fuel and waste oil disposal problems.

Evaluation of a Passive Anion‐Exchange Membrane Micro Fuel Cell Using Glycerol from Several Sources

AbstractThis paper addresses energy generated in a passive anion‐exchange membrane micro fuel cell (PAEMμFC) using glycerol from several kinds of sources: high‐purity glycerol (HPG), saponification process‐derived glycerol (SPDG), crude glycerol from sunflower oil biodiesel (CGSOB) and crude glycerol from cooking oil biodiesel (CGCOB). Spectrophotometry, volumetric Karl Fischer, gas chromatography, calorimetry, Fourier transform infrared, and cyclic voltammetry were employed for the glycerol samples characterization. The PAEMμFC was tested using 0.1M glycerol of each type, achieving power densities of 1.008, 0.932, 0.871, and 0.865 mW cm−2 for HPG, SPDG, CGSOB and CGCOB, respectively. On the other hand, commercially available software from ANSYS, Inc. was used to determine the fuel velocity and pressure in the fuel reservoir and current collector as a complementary evaluation of the PAEMμFC. The results obtained for the prices of the energy of each glycerol sample were presented in order to demonstrate that the cost of energy generated through HPG is approximately 16.5 times the SPDG energy cost and 130 times the CGCOB energy cost.

Mechanical and corrosion properties of brass exposed to waste sunflower oil biodiesel-diesel fuel blends

Biodiesel has recently received increasing attention because of many advantages such as higher cetane number and flash point compared to diesel fuel. However, corrosion of engine parts exposed to biodiesel or biodiesel-diesel fuel blends is still a critical challenge in the biodiesel industry. In the existing literature, there is still a lack of systematic studies including corrosion process in light alloy and changes in mechanical and fuel properties of engine parts (such as brass) after exposure to biodiesel. Therefore, in this study, (1) waste sunflower oil biodiesel (WSOB, B100) was supplied and blended with diesel fuel (B0) at the volume ratios of 10%, 20%, and 40, which are called as B10, B20, and B40, as usual. The important fuel properties of the biodiesel-diesel fuel blends were also analyzed using ASTM test methods. (2) Corrosion characteristics of brass exposed to the biodiesel-diesel fuel blends were determined by means of a static immersion method at room temperature. (3) Mechanical properties of brass were investigated before and after the corrosion test. Finally, (4) variations in surface morphologies of the brass coupons were researched. According to the experimental results, the corrosion rate (0.3810 mpy) of brass exposed to B100 was found to be higher than that of brass exposed to B0 (0.1330 mpy) for the exposure duration of 960 hours. The Brinell hardness numbers (BHN) were determined as 406.265, 477.713, 541.983, 579.448, and 636.602 N/mm2 while the tensile strengths (TS) were 1381.30, 1624.22, 1842.743, 1970.13, and 2164.45 MPa for B0, B10, B20, B40, and B100, respectively. BHN and TS values of B10 were closer to that of B0. Therefore, B10 was found to be a more suitable alternative to diesel fuel in terms of fuel property and corrosion characteristic. The results of this study can promote thermo-physical property collection for biofuels and guide for corrosion studies related to the industrial applications of diesel-biodiesel blends and pure biodiesel.

Biodegradation of biodiesel and toluene under nitrate-reducing conditions and the impact on bacterial community structure

Biodiesel is a renewable fuel that can be mixed with toluene and be accidentally released into anoxic ecosystems and impact soil microbial communities. Therefore, the aim of the present work was to examine, under nitrate-reduction conditions, the biodegradation of toluene in the presence of two different types of biodiesel (sunflower and rapeseed), and their impact on the bacterial community structure. Sediment samples were spiked individually with toluene, biodiesel, and their blends in laboratory-designed microcosms. Sunflower oil biodiesel was produced in the laboratory, while rapeseed oil biodiesel was a commercial product. Degradation of biodiesels and blends was monitored by directly measuring the substrate or indirectly by determining nitrate removal during the course of the experiment. Denitrification rates were estimated with the acetylene inhibition technique. Denaturing gradient gel electrophoresis was used to assess impacts on the bacterial community structure exposed to biodiesels, blends, and toluene. The results of this study showed that toluene and biodiesel were completely degraded within 10 days. Biodiesel significantly affected the bacterial community structure at a similar magnitude, independently of its origin. Additionally, toluene impacted the bacterial community and denitrification process to a lower extent than biodiesel and a clear decrease in the relative bacterial richness and diversity was shown in samples with biodiesel and blends. To the best of our knowledge, this is one of the first reports describing degradation of biodiesel alone and blends under nitrate-reducing conditions, and also the effects of these compounds on the denitrification process. In addition, due to the recently discovered “oxygenic denitrification” process, the acetylene inhibition technique and nitrous oxide quantification may not be the most adequate tool to estimate denitrification rates. Further detailed studies are advised to understand whether the identified bacterial community shift impacts ecosystem functions. Our results help to understand the biodegradation of toluene, biodiesel, and their blends in sediments under nitrate-reducing conditions and might be important in implementing bioremediation strategies in anoxic environments.