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The study on the influence of oxidation degree and temperature on the viscosity of biodiesel

  • Shuang Wang , Meng Sui , Huilong Luo , Fashe Li EMAIL logo and Yuling Zhai EMAIL logo
Published/Copyright: March 12, 2020
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Green Processing and Synthesis
From the journal Green Processing and Synthesis Volume 9 Issue 1

Abstract

Jatropha curcas biodiesel was taken as the research object, studied the single and compound effects of oxidation degree and temperature on kinematic viscosity of biodiesel, and established a mathematical model. The results indicate that the kinematic viscosity of biodiesel decreases gradually with the increase of temperature, and the mathematical model affected by the single factor of temperature is η = e(A + Bt + Ct2) . The kinematic viscosity of biodiesel increases with the increase of oxidation time. The regression equation between kinematic viscosity and conductivity is established as follows: η = A + Bμ. It is found that the influence of temperature on the kinematic viscosity of biodiesel is much greater than that of oxidation, and the higher the temperature, the lower the influence of oxidation on the kinematic viscosity of biodiesel. Through the analysis of the influence weight of two factors and the change rate of kinematic viscosity, it is found that with the increase of temperature, the effect of conductivity on the change rate of kinematic viscosity of biodiesel is positive, but the influence decreases gradually. The relationship between kinematic viscosity, temperature and oxidation

Keywords: biodiesel; degree of oxidation; kinematic viscosity; regression equation
degree is η=(0.179+0.00067μ)e(6.793−0.066t+0.000268t2).

1 Introduction

To cope with the changes of world energy structure, solve the three major problems of oil shortage, environmental pollution and greenhouse effect, and for the reasons of strategic reserves of resources, many countries are actively developing green energy which can be widely used, with little negative effect and little pollution. Biodiesel has been paid much attention to [1,2]. Biodiesel is a kind of renewable liquid fuel [3,4]. It is made from oil crops, engineering microalgae, animal oil and food waste oil by transesterification or thermochemical process.

Biodiesel has the advantages of renewable, biodegradability, non-aromatic and non-sulfur content, low emission [5,6]. Biofuels are carbon neutral fuels, which do not increase carbon dioxide emissions even when burned as fuels. But at the same time, biodiesel mainly consists of saturated fatty acid methyl ester and unsaturated fatty acid methyl ester. Saturated fatty acid methyl ester has high-melting point [7], which makes the low temperature fluidity of biofuels worse. The carbon-carbon double bond and carbon-carbon triple bond in the unsaturated fatty acid methyl ester are easy to oxidize, and the oxidation stability of multiple double bonds is worse because of the synergistic effect [8,9]. Viscosity is one of the key performance indexes of biodiesel, which is related to low temperature fluidity and oxidation stability. High viscosity biodiesel has the disadvantages of poor atomization effect, low combustion efficiency and easy to cause engine wear and tear [10]. In the actual storage and transportation process, unsaturated esters in biodiesel are easily oxidized to form alcohols, aldehydes, organic acids, polymers and precipitates due to the action of oxygen, light, metal ions, etc., resulting in increased biodiesel kinematic viscosity [11]. In low temperature environment, biodiesel is easy to precipitate waxy crystals, which causes blockage of engine pipes and filters, and affects the normal start-up of the engine [12].

In recent years, many models have been proposed to predict the viscosity of biodiesel [13, 14, 15, 16, 17, 18], but multiple factors models about viscosity are scarce. Shu et al. [19] proposed a new topological index, which connected with viscosity, and got two regression equations. By using the regression equation, the viscosity of biodiesel was accurate predicted. Gülüm et al. [20] derived new two-term power models to estimate kinematic viscosities of the blends of biodiesels and commercially available Ultra Force Euro diesel fuel. Compared to the quadratic and Arrhenius type mixing models, these models give the best qualitative and quantitative estimates. Luis [21] developed empirical models to predict both the biodiesel’s density and biodiesel’s viscosity in a wide range of temperature. Juan C. Chavarria-Hernandez et al. [22] proposed three correlations to improve the accuracy in the prediction kinematic viscosity of fatty acid methyl esters (FAMEs) for wide ranges of emperature. Pinzi et al. [23] predicted models of five biodiesel quality properties to predict viscosity, which improve the fittingness of prediction for biodiesel composed by medium chain acids. Yuan et al. [24] combined Grunberg-Nissan equation with a group contribution method as the mixing rule to calculate viscosities of mixtures fatty acid esters in a broad range of both saturated and unsaturated esters.

Up to now, there are no reports about the effect of oxidation degree and temperature on the kinematic viscosity of biodiesel at home and abroad. Therefore, the effects of oxidation degree and temperature on the kinematic viscosity of biodiesel were studied, and the theoretical support was provided for optimizing the low temperature fluidity of biodiesel.

2 Experimental

2.1 Materials and reagents

Preparation process of Jatropha carcass biodiesel: Preliminary biodiesel was prepared by cyclic vapor-phase esterification-transesterification-methanol steam distillation, followed by repeated washing with deionized water (ELGA Lab Water) to remove glycerol and alkaline catalysts. The catalyst is KOH, the dosage is 3%, and volume ratio of raw oil and methanol is 1:3. The reaction time and temperature are 80 min and 85°C, respectively, and the uncertainty values of temperature are ±0.5°C. The water bath is agitated and heated. After refining by vacuum rotary evaporator (R-215, BUCHI), the refined biodiesel can be obtained [25]. Table 1 is the physical and chemical properties of Jatropha carcass biodiesel and the European standard. Table 2 is the composition of fatty acids in Jatropha biodiesel.

Table 1

European standard for biodiesel and physic-chemical performance index of Jatropha biodiesel.

ProjectQuality indexJatropha biodieselExperiment method
Density (15°C), kg/m3860~900862ISO 3104
Kinematic viscosity (40°C), mm2/s3.5~5.04.52ISO 3104
Flash point, °C≥120185ISO 3679
Sulfur content (Quality score), %≤0.00100.002ISO 20884
10% Conradson carbon (Quality score), %≤0.30.063ISO 10370
Sulphate ash (Quality score), %≤0.020.0013ISO 3987
Moisture content (mg/kg)5001190ISO 12937
Copper corrosion (50°C, 3h), degree≤11aISO 2160
Cetane number≥5151ISO 5165
Oxidation stability (110°C), h≥6.00.76EN14112
Acid value, mgKOH/g≤0.502.96EN 14104
Free glycerol content (Quality score), %≤0.020.01EN 14105
Total glycerol content (Quality score), %≤0.250.17EN 14105
Table 2

Composition of fatty acids in Jatropha biodiesel.

CompositionC14:0C16:0C16:1C18:0C18:1C18:2C18:3C20:0
Content, %0.1313.100.397.7838.1839.520.650.25

2.2 Experiment method

Rancimat instrument (Rancimat 873 biodiesel oxidation stability tester, Switzerland Wantong China Limited) was used to determine the oxidation degree of biodiesel [26,27]. Rancimat assay (EN 14112-2003): the temperature of sample is 110°C, continuously injected into the air, and the air flow rate is 10 L/h. The duration of the test varies according to the conductivity. The unstable secondary oxidation products are carried by the flowing air into another glass bottle filled with ultra-pure water (Classic Villa Biological Laboratory Ultra-Pure Water Instrument, ELGA Lab Water, UK). In this process, the electric conductivity of ultra-pure water changes constantly (the uncertain tie of conductivity is ±0.5 μS/cm). The change of electric conductivity of ultra-pure water is measured by electrodes, and a curve between electric conductivity and time is obtained by plotting the electric conductivity and time. In this paper, conductivity and oxidation time are used as indicators of oxidation degree respectively. An experimental setup for oxidizing biodiesel is shown in Figure 1. A typical curve of conductivity vs time is shown in Figure 2.

Figure 1 An experimental setup for oxidizing biodiesel.
Figure 1

An experimental setup for oxidizing biodiesel.

Figure 2 The curve of conductivity and time.
Figure 2

The curve of conductivity and time.

The viscosity of biodiesel was determined according to standard GB/T265-1988. The experimental apparatus is the viscosity tester of the oil product (Shanghai Changji Geological Instrument Co., Ltd.). The uncertainty value of viscosity is ±3%.

3 Results and discussion

3.1 The effect of temperature on the kinematic viscosity of biodiesel

Biodiesel has the characteristics of high freezing point and poor fluidity at low temperature. At low temperature, the kinematic viscosity of biodiesel will change dramatically, and the kinematic viscosity change law is not obvious [28, 29, 30, 31, 32, 33, 34]. When using biodiesel, to improve the fluidity of biodiesel, improve the atomization effect and combustion efficiency of biodiesel, it is usually used at room temperature or under the condition of preheating. At low temperatures, biodiesel can be used to improve its low temperature fluidity by adding a pour point depressant. The kinematic viscosity of Jatropha curcas biodiesel with different oxidation degree at different temperatures was tested and analyzed by empirical formula. The regression Eq. 1 of kinematic viscosity of biodiesel was proposed by us for optimization.

(1)η=e(A+Bt+Ct2)

The η in Eq. 1 is kinematic viscosity (mm2/s) and t is centigrade (°C). Using the optimized empirical formula, the kinematic viscosity and temperature of Jatropha curcas biodiesel with different oxidation degree were treated. The optimized empirical equation of kinematic viscosity and temperature of biodiesel was obtained as shown in Table 3. In this study, the oxidation degree of Jatropha curcas biodiesel was based on the ultra-pure water conductivity (μS/cm) of oxidation stability tester.

Table 3

Empirical equation for kinematic viscosity and temperature of Jatropha curcas biodiesel.

Conductivity μS/cmEmpirical equationR2
0η = e(23.45 − 0.12t + 0.0001t2)0.9995
50η = e(18.81 − 0.11t + 0.0001t2)0.9967
100η = e(20.84 − 0.1t + 0.0001t2)0.9999
150η = e(20.26 − 0.11t + 0.0001t2)0.9999

The curve of regression equation was plotted and analyzed with the experimental data. Figure 3 is a fitting diagram of the empirical equation of kinematic viscosity and temperature of biodiesel with four different conductivity, as well as the measured value of kinematic viscosity.

Figure 3 The curve fitting of kinematic viscosity and temperature of biodiesel with different conductivity.
Figure 3

The curve fitting of kinematic viscosity and temperature of biodiesel with different conductivity.

It can be seen from the diagram that the kinematic viscosity of Jatropha curcas biodiesel with different oxidation degree decreases gradually with the increase of temperature, and the change trend is the same as that of biodiesel without oxidation modification. Among them, the kinematic viscosity of Jatropha curcas biodiesel was well distributed on the fitting curve, and the correlation coefficient R2 was above 0.99. The oxidation degree of biodiesel has little influence on biodiesel viscosity variation with temperature, and can still be predicted by Eq. 1.

3.2 Effect of oxidation degree (conductivity/oxidation time) on the kinematic viscosity of biodiesel

The polynomial η = anτn + an-1τn-1 + … + a1τ + a0 fitting equation was used to fit the non-linear curve of kinematic viscosity of Jatropha curcas biodiesel with different oxidation time. The empirical equation was obtained as shown in Table 4. To get the function relationship between kinematic viscosity η and oxidation time τ of Jatropha curcas biodiesel accurately, the experimental data were fitted by 2/3/4 order function.

Table 4

The empirical equation of kinematic viscosity and oxidation time of Jatropha curcas biodiesel at 25°C temperature.

OrderEmpirical equationNumberR2
2η = 4.822 − 0.042τ + 0.0096τ2(2)0.9461
3η = 4.705 + 0.111τ − 0.031τ2 + 0.001τ3(3)0.9874
4η = 4.745 − 0.025τ + 0.031τ2 − 0.0044τ3 + 0.0002τ4(4)0.9987

  1. τ – time, h; η – kinematic viscosity, mm2/s.

The regression equation curves and the kinematic viscosity values of the biodiesel were plotted and analyzed. Figure 4 is a fitting diagram of the kinematic viscosity and oxidation time of the biodiesel with three different orders.

Figure 4 Curve fitting of kinematic viscosity and oxidation time of Jatropha curcas biodiesel.
Figure 4

Curve fitting of kinematic viscosity and oxidation time of Jatropha curcas biodiesel.

The kinematic viscosity of biodiesel increases with the increase of oxidation time. Through the fitting curve of 2/3/4 order polynomial, the functional relationship between kinematic viscosity η and oxidation time τ of Jatropha curcas biodiesel can be obtained, and the correlation coefficients R2 are all greater than 0.94. With the increase of the order of polynomials, the correlation coefficient increases more than 0.99. With the increase of the order of polynomial, the sum of the square of the residuals between the measured kinematic viscosity and the curve fitting becomes smaller and smaller. The sum of the square of the residuals of 2/3/4 polynomial fitting is 0.097, 0.023 and 0.00329, respectively.

The fitting formula of kinematic viscosity and conductivity is Eq. 5. The regression equation curves were drawn and the kinematic viscosity values of the biodiesel were analyzed. Figure 5 was a linear fitting diagram of the kinematic viscosity and electrical conductivity of the biodiesel at 20/40/60/80°C.

Figure 5 The linear fitting results of kinematic viscosity and conductivity of Jatropha curcas biodiesel.
Figure 5

The linear fitting results of kinematic viscosity and conductivity of Jatropha curcas biodiesel.

(5)η=A+Bμ

where η is kinematic viscosity (mm2/s) and μ is conductivity (mm2/s).

Through the comparative analysis of Table 5 and Figure 5, it can be concluded that the kinematic viscosity of Jatropha curcas biodiesel is linearly related to the conductivity, and the correlation coefficients R2 at 20/40/60/80°C are 0.978/0.978/0.979/0.962, respectively. This coefficient is larger than the correlation coefficient of the second-order fitting curve of kinematic viscosity and oxidation time, and less than the correlation coefficient of the third-order fitting curve of kinematic viscosity and oxidation time. However, the relationship between conductivity and kinematic viscosity of Jatropha curcas biodiesel is relatively simple and clear.

Table 5

The empirical equation for kinematic viscosity and conductivity of biodiesel.

Temperature, °CEmpirical equationR2
20η = 6.85 + 0.0123μ0.9787
40η = 4.265 + 0.0063μ0.9786
60η = 2.94 + 0.0037μ0.9798
80η = 2.193 + 0.0021μ0.9625

3.3 The effect of oxidation degree and temperature on kinematic viscosity of biodiesel

The results indicate that the regression equation is only obtained under the condition that a single dependent variable (temperature/oxidation degree) affects the kinematic viscosity of Jatropha curcas biodiesel. In practical engineering applications, the kinematic viscosity of biodiesel is affected by multiple dependent variables. To obtain the functional relationship between the kinematic viscosity η of the Jatropha curcas biodiesel and the conductivity μ and the temperature t, the kinematic viscosity, conductivity and temperature of Jatropha curcas biodiesel were fitted by Eq. 6 and 7 two regression equations. The empirical equation is shown in Table 6.

Table 6

The empirical equations for kinematic viscosity, oxidation degree and temperature of biodiesel.

Serial numberEmpirical equationR2
(6)’η=(0.179+0.00067μ)e(6.793−0.066t+0.000268t2)0.9984
(7)’η=0.194+0.007μ+e(2.609−0.035t+0.0001t2)0.9916

  1. μ – conductivity, μS/cm; t – temperature, °C; η – kinematic viscosity, mm2/s.

(6)z=(A+Bx)e(C+Dy+Ey2)
(7)z=A+Bx+e(C+Dy+Ey2)

The regression equation curve was plotted and the kinematic viscosity of the biodiesel was analyzed. Figure 6 is a non-linear surface fitting diagram of the three: the empirical equation of kinematic viscosity, conductivity and temperature of biodiesel and the experimental measurement of kinematic viscosity of biodiesel.

Figure 6 The nonlinear surface fitting of kinematic viscosity, conductivity and temperature of Jatropha curcas biodiesel.
Figure 6

The nonlinear surface fitting of kinematic viscosity, conductivity and temperature of Jatropha curcas biodiesel.

Through comparative analysis of Table 6 and Figure 6, it is found that: The fitting correlation coefficients R2 of surface Eq. 6’ and surface Eq. 7’ are 0.998 and 0.991 respectively for three-dimensional scatter plots. The difference between Eq. 6’ and Eq. 7’ is that Eq. 6’ considers the internal relationship between temperature and oxidation rate in the oxidation process of biodiesel. When the temperature rises, the chain oxidation reaction accelerates and the oxidation degree increases slightly, which influences the kinematic viscosity of biodiesel. Eq. 7’ uses a simple polynomial accumulation of two factors acting alone, ignoring the effect of temperature on oxidation rate. The structure of surface Eq. 6’ is complex, with two polynomial and two roots. The structure of surface Eq. 7’ is only the sum of a polynomial and exponential, and relatively simple. In the analysis of specific problems, if the correlation requirements are high, the use of Eq. 6 analysis; for the calculation speed and equation simple requirements are high, the use of Eq. 7 analysis.

Further analysis of surface Eq. 7’ shows that neglecting the binomial coefficient of 0.0001 (0), the coefficient of temperature t is −0.35, the coefficient of conductivity μ is 0.007, and the absolute value of temperature t coefficient is five times that of conductivity coefficient. In the single factor test, when the conductivity is 0/10/20/30/40/50/60/70/80/90/100 /110 μS/cm, when the temperature rises from 10°C to 80°C, the decrease of kinematic viscosity Δη is about 7.16~9.28 mm2/s. When the temperature is 10/15/20/25/ 30/35/40/45/50/55/60/65/70/75/80°C, and the conductivity increases from 0 μS/cm to 150 μS/cm, the increase of kinematic viscosity Δη is about 0.28~2.30 mm2/s. When the temperature is 80°C, the increase of kinematic viscosity caused by oxidation is only 0.28 mm2/s. The results indicate that the influence of temperature on the kinematic viscosity of biodiesel is greater than that of oxidation degree. The higher the temperature is, the lower the influence of oxidation degree on the kinematic viscosity of biodiesel is.

3.4 The comparative analysis of temperature and oxidation degree on the change rate of kinematic viscosity

To further analyze the influence of temperature and oxidation degree on the kinematic viscosity change rate of biodiesel, partial derivatives of ∂η∂μ   and   ∂η∂twere calculated for fitting Eq. 7’. The results are as follows Eq. 8 and 9.

(8)∂η∂μ=0.007
(9)∂η∂t=e(2.609−0.035t+0.0001t2)(0.0002t−0.035)

The partial derivative curve of the fitting equation is obtained by drawing the partial derivative Eq. 9. As shown in Figure 7.

Figure 7 The partial derivative curve of ∂η∂t.$\frac{\partial \eta }{\partial t}.$
Figure 7

The partial derivative curve of ∂η∂t.

By comparing the Eq. 8 and Figure 7, it is found that the slope of the line projected by the tangent of t = t0 intersecting line at point (μ0,t0,f(μ0,t0)) on the μ0η plane is 0.007. Because the intersection line between the fitting surface and t = t0 is a straight line, 0.007 is the slope of the straight line. Its physical meaning is that the change rate of kinematic viscosity of Jatropha curcas biodiesel is +0.007 mm2/s with the increase of conductivity in the range of experimental temperature and oxidation degree. The partial derivative of ∂η∂tis a curve, within the experimental range, the longitudinal axis value is less than 0, indicating that the temperature has a negative effect on the kinematic viscosity change rate of biodiesel, and the kinematic viscosity decreases with the increase of temperature. At the test temperature of 80°C, the influence of temperature on the change rate of biodiesel viscosity is −0.0297 mm2/s.

For fitting Eq. 6’, ∂η∂μ    and    ∂η∂tpartial derivatives areobtained. Because the partial derivative equation is more complex, it is difficult to analyze by the equation, so the partial derivative equation is plotted. The results are indicated in Figures 8 and 9.

Figure 8 The partial derivative function diagram of ∂η∂μ.$\frac{\partial \eta }{\partial \mu }.$
Figure 8

The partial derivative function diagram of ∂η∂μ.

Figure 9 The partial derivative function diagram of ∂η∂t.$\frac{\partial \eta }{\partial t}.$
Figure 9

The partial derivative function diagram of ∂η∂t.

Comparing with Figures 8 and 9, it can be found that the slope of projection on μ0η plane decreases with the increase of conductivity, that is, with the increase of temperature, the effect of conductivity on the change rate of kinematic viscosity of biodiesel is positive, but the influence decreases gradually.

The results of partial derivative analysis of Eq. 7’ are quite different from those of Table 4. The results of partial derivative analysis of Eq. 6’ have the same trend as those of straight line slope in Table 4. The results of partial derivative analysis show that the fitting Eq. 6’ reflects the experimental data more authentically, and proves that the functional relationship between kinematic viscosity of biodiesel, temperature and oxidation degree is not a simple first-order dependent variable fitting equation, but a second-order dependent variable fitting equation.

4 Conclusions

  1. The kinematic viscosity of biodiesel gradually decreases with increasing temperature. The kinematic viscosity of biodiesel before and after oxidation has the same change trend with temperature. The correlation coefficient is above 0.99 by Eq. 1 regression equation.

  2. The kinematic viscosity of biodiesel increased with the increase of oxidation time. The correlation coefficient of kinematic viscosity η and oxidation time τ of Jatropha curcas biodiesel was generally greater than 0.94.

  3. The kinematic viscosity of Jatropha curcas biodiesel was linearly correlated with electrical conductivity, and the data were processed by Eq. 5 regression equation. When the temperature is 20/40/60/80°C, the fitting linear correlation coefficient of kinematic viscosity and conductivity is 0.978/0.978/0.979/0.962, respectively.

  4. By comparing the two influencing factors of kinematic viscosity of biodiesel, it is found that the influence of temperature is greater than that of oxidation degree. The higher the temperature is, the lower the influence of oxidation degree on kinematic viscosity of biodiesel is. It can be fitted by two regression equations Eq. 6 and 7, and the correlation coefficient is over 0.99.

  5. With the increase of temperature, the effect of conductivity on the kinematic viscosity of biodiesel is positive, but the influence decreases gradually. The functional relationship between kinematic viscosity of biodiesel, temperature and oxidation degree is a second-order dependent variable fitting equation, and the fitting equation Eq. 6’ is closer to the actual situation.

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Received: 2019-09-17
Accepted: 2019-12-01
Published Online: 2020-03-12

© 2020 Wang et al., published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

Articles in the same Issue

  1. Obituary for Prof. Dr. Jun-ichi Yoshida
  2. Regular Articles
  3. Optimization of microwave-assisted manganese leaching from electrolyte manganese residue
  4. Crustacean shell bio-refining to chitin by natural deep eutectic solvents
  5. The kinetics of the extraction of caffeine from guarana seed under the action of ultrasonic field with simultaneous cooling
  6. Biocomposite scaffold preparation from hydroxyapatite extracted from waste bovine bone
  7. A simple room temperature-static bioreactor for effective synthesis of hexyl acetate
  8. Biofabrication of zinc oxide nanoparticles, characterization and cytotoxicity against pediatric leukemia cell lines
  9. Efficient synthesis of palladium nanoparticles using guar gum as stabilizer and their applications as catalyst in reduction reactions and degradation of azo dyes
  10. Isolation of biosurfactant producing bacteria from Potwar oil fields: Effect of non-fossil fuel based carbon sources
  11. Green synthesis, characterization and photocatalytic applications of silver nanoparticles using Diospyros lotus
  12. Dielectric properties and microwave heating behavior of neutral leaching residues from zinc metallurgy in the microwave field
  13. Green synthesis and stabilization of silver nanoparticles using Lysimachia foenum-graecum Hance extract and their antibacterial activity
  14. Microwave-induced heating behavior of Y-TZP ceramics under multiphysics system
  15. Synthesis and catalytic properties of nickel salts of Keggin-type heteropolyacids embedded metal-organic framework hybrid nanocatalyst
  16. Preparation and properties of hydrogel based on sawdust cellulose for environmentally friendly slow release fertilizers
  17. Structural characterization, antioxidant and cytotoxic effects of iron nanoparticles synthesized using Asphodelus aestivus Brot. aqueous extract
  18. Phase transformation involved in the reduction process of magnesium oxide in calcined dolomite by ferrosilicon with additive of aluminum
  19. Green synthesis of TiO2 nanoparticles from Syzygium cumini extract for photo-catalytic removal of lead (Pb) in explosive industrial wastewater
  20. The study on the influence of oxidation degree and temperature on the viscosity of biodiesel
  21. Prepare a catalyst consist of rare earth minerals to denitrate via NH3-SCR
  22. Bacterial nanobiotic potential
  23. Green synthesis and characterization of carboxymethyl guar gum: Application in textile printing technology
  24. Potential of adsorbents from agricultural wastes as alternative fillers in mixed matrix membrane for gas separation: A review
  25. Bactericidal and cytotoxic properties of green synthesized nanosilver using Rosmarinus officinalis leaves
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  33. Green synthesis of metal and metal oxide nanoparticles from plant leaf extracts and their applications: A review
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  54. Effect of KMnO4 on catalytic combustion performance of semi-coke
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  56. Nucleotide-based green synthesis of lanthanide coordination polymers for tunable white-light emission
  57. Determination of life cycle GHG emission factor for paper products of Vietnam
  58. Parabolic trough solar collectors: A general overview of technology, industrial applications, energy market, modeling, and standards
  59. Structural characteristics of plant cell wall elucidated by solution-state 2D NMR spectroscopy with an optimized procedure
  60. Sustainable utilization of a converter slagging agent prepared by converter precipitator dust and oxide scale
  61. Efficacy of chitosan silver nanoparticles from shrimp-shell wastes against major mosquito vectors of public health importance
  62. Effectiveness of six different methods in green synthesis of selenium nanoparticles using propolis extract: Screening and characterization
  63. Characterizations and analysis of the antioxidant, antimicrobial, and dye reduction ability of green synthesized silver nanoparticles
  64. Foliar applications of bio-fabricated selenium nanoparticles to improve the growth of wheat plants under drought stress
  65. Green synthesis of silver nanoparticles from Valeriana jatamansi shoots extract and its antimicrobial activity
  66. Characterization and biological activities of synthesized zinc oxide nanoparticles using the extract of Acantholimon serotinum
  67. Effect of calcination temperature on rare earth tailing catalysts for catalytic methane combustion
  68. Enhanced diuretic action of furosemide by complexation with β-cyclodextrin in the presence of sodium lauryl sulfate
  69. Development of chitosan/agar-silver nanoparticles-coated paper for antibacterial application
  70. Preparation, characterization, and catalytic performance of Pd–Ni/AC bimetallic nano-catalysts
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  72. Review Articles
  73. Recent advances in the catalytic applications of GO/rGO for green organic synthesis
https://doi.org/10.1515/gps-2020-0019
Keywords for this article
biodiesel; degree of oxidation; kinematic viscosity; regression equation
Creative Commons
BY 4.0

Articles in the same Issue

  1. Obituary for Prof. Dr. Jun-ichi Yoshida
  2. Regular Articles
  3. Optimization of microwave-assisted manganese leaching from electrolyte manganese residue
  4. Crustacean shell bio-refining to chitin by natural deep eutectic solvents
  5. The kinetics of the extraction of caffeine from guarana seed under the action of ultrasonic field with simultaneous cooling
  6. Biocomposite scaffold preparation from hydroxyapatite extracted from waste bovine bone
  7. A simple room temperature-static bioreactor for effective synthesis of hexyl acetate
  8. Biofabrication of zinc oxide nanoparticles, characterization and cytotoxicity against pediatric leukemia cell lines
  9. Efficient synthesis of palladium nanoparticles using guar gum as stabilizer and their applications as catalyst in reduction reactions and degradation of azo dyes
  10. Isolation of biosurfactant producing bacteria from Potwar oil fields: Effect of non-fossil fuel based carbon sources
  11. Green synthesis, characterization and photocatalytic applications of silver nanoparticles using Diospyros lotus
  12. Dielectric properties and microwave heating behavior of neutral leaching residues from zinc metallurgy in the microwave field
  13. Green synthesis and stabilization of silver nanoparticles using Lysimachia foenum-graecum Hance extract and their antibacterial activity
  14. Microwave-induced heating behavior of Y-TZP ceramics under multiphysics system
  15. Synthesis and catalytic properties of nickel salts of Keggin-type heteropolyacids embedded metal-organic framework hybrid nanocatalyst
  16. Preparation and properties of hydrogel based on sawdust cellulose for environmentally friendly slow release fertilizers
  17. Structural characterization, antioxidant and cytotoxic effects of iron nanoparticles synthesized using Asphodelus aestivus Brot. aqueous extract
  18. Phase transformation involved in the reduction process of magnesium oxide in calcined dolomite by ferrosilicon with additive of aluminum
  19. Green synthesis of TiO2 nanoparticles from Syzygium cumini extract for photo-catalytic removal of lead (Pb) in explosive industrial wastewater
  20. The study on the influence of oxidation degree and temperature on the viscosity of biodiesel
  21. Prepare a catalyst consist of rare earth minerals to denitrate via NH3-SCR
  22. Bacterial nanobiotic potential
  23. Green synthesis and characterization of carboxymethyl guar gum: Application in textile printing technology
  24. Potential of adsorbents from agricultural wastes as alternative fillers in mixed matrix membrane for gas separation: A review
  25. Bactericidal and cytotoxic properties of green synthesized nanosilver using Rosmarinus officinalis leaves
  26. Synthesis of biomass-supported CuNi zero-valent nanoparticles through wetness co-impregnation method for the removal of carcinogenic dyes and nitroarene
  27. Synthesis of 2,2′-dibenzoylaminodiphenyl disulfide based on Aspen Plus simulation and the development of green synthesis processes
  28. Catalytic performance of the biosynthesized AgNps from Bistorta amplexicaule: antifungal, bactericidal, and reduction of carcinogenic 4-nitrophenol
  29. Optical and antimicrobial properties of silver nanoparticles synthesized via green route using honey
  30. Adsorption of l-α-glycerophosphocholine on ion-exchange resin: Equilibrium, kinetic, and thermodynamic studies
  31. Microwave-assisted green synthesis of silver nanoparticles using dried extracts of Chlorella vulgaris and antibacterial activity studies
  32. Preparation of graphene oxide/chitosan complex and its adsorption properties for heavy metal ions
  33. Green synthesis of metal and metal oxide nanoparticles from plant leaf extracts and their applications: A review
  34. Synthesis, characterization, and electrochemical properties of carbon nanotubes used as cathode materials for Al–air batteries from a renewable source of water hyacinth
  35. Optimization of medium–low-grade phosphorus rock carbothermal reduction process by response surface methodology
  36. The study of rod-shaped TiO2 composite material in the protection of stone cultural relics
  37. Eco-friendly synthesis of AuNPs for cutaneous wound-healing applications in nursing care after surgery
  38. Green approach in fabrication of photocatalytic, antimicrobial, and antioxidant zinc oxide nanoparticles – hydrothermal synthesis using clove hydroalcoholic extract and optimization of the process
  39. Green synthesis: Proposed mechanism and factors influencing the synthesis of platinum nanoparticles
  40. Green synthesis of 3-(1-naphthyl), 4-methyl-3-(1-naphthyl) coumarins and 3-phenylcoumarins using dual-frequency ultrasonication
  41. Optimization for removal efficiency of fluoride using La(iii)–Al(iii)-activated carbon modified by chemical route
  42. In vitro biological activity of Hydroclathrus clathratus and its use as an extracellular bioreductant for silver nanoparticle formation
  43. Evaluation of saponin-rich/poor leaf extract-mediated silver nanoparticles and their antifungal capacity
  44. Propylene carbonate synthesis from propylene oxide and CO2 over Ga-Silicate-1 catalyst
  45. Environmentally benevolent synthesis and characterization of silver nanoparticles using Olea ferruginea Royle for antibacterial and antioxidant activities
  46. Eco-synthesis and characterization of titanium nanoparticles: Testing its cytotoxicity and antibacterial effects
  47. A novel biofabrication of gold nanoparticles using Erythrina senegalensis leaf extract and their ameliorative effect on mycoplasmal pneumonia for treating lung infection in nursing care
  48. Phytosynthesis of selenium nanoparticles using the costus extract for bactericidal application against foodborne pathogens
  49. Temperature effects on electrospun chitosan nanofibers
  50. An electrochemical method to investigate the effects of compound composition on gold dissolution in thiosulfate solution
  51. Trillium govanianum Wall. Ex. Royle rhizomes extract-medicated silver nanoparticles and their antimicrobial activity
  52. In vitro bactericidal, antidiabetic, cytotoxic, anticoagulant, and hemolytic effect of green-synthesized silver nanoparticles using Allium sativum clove extract incubated at various temperatures
  53. The green synthesis of N-hydroxyethyl-substituted 1,2,3,4-tetrahydroquinolines with acidic ionic liquid as catalyst
  54. Effect of KMnO4 on catalytic combustion performance of semi-coke
  55. Removal of Congo red and malachite green from aqueous solution using heterogeneous Ag/ZnCo-ZIF catalyst in the presence of hydrogen peroxide
  56. Nucleotide-based green synthesis of lanthanide coordination polymers for tunable white-light emission
  57. Determination of life cycle GHG emission factor for paper products of Vietnam
  58. Parabolic trough solar collectors: A general overview of technology, industrial applications, energy market, modeling, and standards
  59. Structural characteristics of plant cell wall elucidated by solution-state 2D NMR spectroscopy with an optimized procedure
  60. Sustainable utilization of a converter slagging agent prepared by converter precipitator dust and oxide scale
  61. Efficacy of chitosan silver nanoparticles from shrimp-shell wastes against major mosquito vectors of public health importance
  62. Effectiveness of six different methods in green synthesis of selenium nanoparticles using propolis extract: Screening and characterization
  63. Characterizations and analysis of the antioxidant, antimicrobial, and dye reduction ability of green synthesized silver nanoparticles
  64. Foliar applications of bio-fabricated selenium nanoparticles to improve the growth of wheat plants under drought stress
  65. Green synthesis of silver nanoparticles from Valeriana jatamansi shoots extract and its antimicrobial activity
  66. Characterization and biological activities of synthesized zinc oxide nanoparticles using the extract of Acantholimon serotinum
  67. Effect of calcination temperature on rare earth tailing catalysts for catalytic methane combustion
  68. Enhanced diuretic action of furosemide by complexation with β-cyclodextrin in the presence of sodium lauryl sulfate
  69. Development of chitosan/agar-silver nanoparticles-coated paper for antibacterial application
  70. Preparation, characterization, and catalytic performance of Pd–Ni/AC bimetallic nano-catalysts
  71. Acid red G dye removal from aqueous solutions by porous ceramsite produced from solid wastes: Batch and fixed-bed studies
  72. Review Articles
  73. Recent advances in the catalytic applications of GO/rGO for green organic synthesis
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