Description:DESCRIPTION:
Field of the invention:
The present invention relates to the technical field of biodiesel production, and more particularly, to a method for producing high-purity biodiesel from neem oil using laser pre-treatment and a Calcium oxide (CaO) nanocatalyst to achieve enhanced efficiency and yield.
Background of the invention:
Biodiesel is an alternative fuel similar to conventional or 'fossil' diesel. Biodiesel is derived from renewable sources such as vegetable oils, animal fats, and used cooking oils. Biodiesel is biodegradable, non-toxic, and emits significantly fewer pollutants than petroleum diesel, making it an environmentally friendly option. Among various sources, neem oil has garnered attention due to its potential as a biodiesel feedstock owing to its high oil content and availability in many regions.
Traditional biodiesel production methods from neem oil often involve chemical processes such as transesterification, which typically require significant energy input, time, and chemical catalysts. These processes can be complex, costly, and environmentally taxing due to the chemicals used and the waste generated. Additionally, the yield and purity of biodiesel produced through these methods can vary, thereby impacting the overall efficiency and economic viability of biodiesel production.
Recent advancements in biodiesel production aim to enhance efficiency and yield while minimizing environmental impact. One such advancement is the use of nanocatalysts. Nanocatalysts, due to their high surface area and unique properties, have shown promise in improving the reaction rates and reducing the amount of catalyst required. However, despite these improvements, there remain challenges in achieving consistently high yields and purity levels in biodiesel production.
Another innovative approach is the application of laser pre-treatment in the biodiesel production process. Laser pre-treatment has been found to enhance the reactivity of oils by modifying their physical and chemical properties. This method can potentially reduce the energy requirements and improve the overall efficiency of the biodiesel production process. However, combining laser pre-treatment with an efficient catalyst system remains an area of active research to optimize the process for commercial viability.
By addressing these aforementioned limitations, there is a need for a method of producing high-purity biodiesel from neem oil using laser pre-treatment and a CaO nanocatalyst to achieve enhanced efficiency and yield. There is also a need for a method that improves the efficiency and yield of biodiesel production, thereby offering a sustainable and cost-effective alternative to traditional fossil fuels. Further, there is also a need for a method that enhances economic feasibility of biodiesel production and reduces the environmental impact associated with conventional diesel fuel.
Objectives of the invention:
The primary objective of the invention is to provide a method for producing high-purity biodiesel from neem oil using laser pre-treatment and a Calcium oxide (CaO) nanocatalyst to achieve enhanced efficiency and yield.
Another objective of the invention is to enhance the efficiency and yield of biodiesel production from neem oil through the integration of laser pre-treatment, which modifies the physical and chemical properties of neem oil to improve its reactivity.
Another objective of the invention is to utilize a CaO nanocatalyst in the biodiesel production process, thereby leveraging its high surface area and unique catalytic properties to accelerate the transesterification reaction and reduce the amount of catalyst required.
Another objective of the invention is to minimize the environmental impact of biodiesel production by reducing the energy requirements and chemical waste associated with traditional methods, thereby offering a more sustainable and eco-friendly approach.
Another objective of the invention is to provide a cost-effective method for biodiesel production that enhances the economic feasibility of using neem oil as a feedstock, thereby making biodiesel a more viable alternative to conventional diesel fuels.
Another objective of the invention is to ensure consistent high-purity biodiesel output, thereby improving the overall quality and performance of the biodiesel produced from neem oil.
Another objective of the invention is to develop a scalable and commercially viable biodiesel production process that can be easily adapted and implemented in various production settings, from small-scale to large-scale operations.
Yet another objective of the invention is to contribute to the reduction of greenhouse gas emissions and dependence on fossil fuels by providing an efficient method for producing renewable biodiesel from neem oil.
The further objective of the invention is to improve the overall sustainability of biodiesel production by utilizing a renewable and readily available feedstock, neem oil, and optimizing the production process to minimize waste and energy consumption.
Summary of the invention:
The present disclosure proposes a method for producing high-purity biodiesel from neem oil using laser pre-treatment. The following presents a simplified summary in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview. It is not intended to identify key or critical elements or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
In order to overcome the deficiencies of the prior art, the present disclosure is to solve the technical problem of providing a method for producing high-purity biodiesel from neem oil using laser pre-treatment and a CaO nanocatalyst to achieve enhanced efficiency and yield.
According to one aspect, the invention discloses a method that improves the efficiency and yield of biodiesel production, thereby offering a sustainable and cost-effective alternative to traditional fossil fuels. The method enhances economic feasibility of biodiesel production and reduces the environmental impact associated with conventional diesel fuel.
In one embodiment herein, the method is disclosed for producing high-purity biodiesel from neem oil. First, at one step, the neem oil is pre-treated using a green laser with a wavelength of 532 nm for a duration of at least 30 minutes to enhance the reactivity of the neem oil and reduce the formation of unwanted by-products. At another step, the free fatty acid (FFA) content of the neem oil is determined using a titration method. At another step, acid esterification is performed if the FFA content is greater than 2% to reduce it to less than 2%. At another step, the neem oil is mixed with methanol and a calcium oxide (CaO) nanocatalyst in appropriate amounts to initiate a transesterification reaction, thereby obtaining a reaction mixture.
At another step, the reaction mixture is maintained under controlled conditions of temperature, duration, catalyst loading, and oil-methanol molar ratio. At another step, the reaction mixture is allowed to separate into biodiesel and glycerol layers. Further, at another step, the biodiesel is cleaned for a duration of 2 hr using an air bubble wash process to remove excess alcohol, water, and catalyst residues, thereby producing the high-quality biodiesel.
In one embodiment herein, the neem oil is produced by cold pressing raw neem seeds to extract the neem oil. The extracted neem oil is heated to a temperature of at least 110±5 °C to remove moisture present in the neem oil, and then filtered using a filter paper to remove impurities, thereby producing the neem oil for the transesterification reaction.
In one embodiment herein, the CaO nanocatalyst is synthesized using a sol-gel method. This synthesis involves dissolving 11.81 g of calcium nitrate tetrahydrate (Ca(NO3)2·4H2O) in 25 ml of ethylene glycol to create a sol, allowing the sol to rest for a duration of at least 5 hr to form a gel, filtering the gel using distilled water and a filter paper, drying the filtered gel in a hot air oven at a specific temperature to obtain a dried gel, grinding the dried gel into a fine powder using a mortar and pestle, and calcining the powdered material in a muffle furnace at a temperature of at least 850° C for a duration of at least 1 hr.
In one embodiment herein, the transesterification reaction is carried out at a temperature varying between 40 °C and 70 °C. In one embodiment herein, the transesterification reaction is conducted for a duration of at least 60 to 150 min.
In one embodiment herein, the transesterification reaction is optimized by varying the molar ratio of neem oil to methanol within the range of 1:10 to 1:25 and adjusting the weight percentage of the CaO nanocatalyst within the range of 0.5% to 1.25% to achieve maximum biodiesel yield.
In one embodiment herein, the separation of the biodiesel from the reaction mixture is achieved by transferring the reaction mixture to a separating funnel, allowing the reaction mixture to settle for a time duration sufficient to separate the biodiesel from glycerol and other impurities, and extracting the biodiesel layer from the separating funnel, thereby leaving behind the glycerol and impurities.
Further, objects and advantages of the present invention will be apparent from a study of the following portion of the specification, the claims, and the attached drawings.
Detailed description of drawings:
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and, together with the description, explain the principles of the invention.
FIG. 1 illustrates a flowchart of a method for producing high-purity biodiesel from neem oil, in accordance to an example embodiment of the invention.
FIG. 2 illustrates a schematic representation of a synthesis process for a calcium oxide (CaO) nanocatalyst, in accordance to an example embodiment of the invention.
FIGs. 3A-3D illustrate scanning electron microscope (SEM) images of synthesized nanocatalyst at 5 µm, 10 µm, 20 µm, and 100 µm magnification, respectively, in accordance to an example embodiment of the invention.
FIG. 4 illustrates a graphical representation depicting an X-ray diffraction (XRD) pattern of the synthesized CaO nanocatalyst, in accordance to an example embodiment of the invention.
FIGs. 5A and 5B illustrate graphical representations depicting Fourier Transform Infrared (FTIR) spectra of neem oil and laser-treated neem oil, in accordance to an example embodiment of the invention.
FIGs. 6A–6D illustrate graphical representations of Hydrogen nuclear magnetic resonance (H-NMR) spectra for neem oil methyl ester (NOME) and laser-treated neem oil methyl ester (LNOME) conversion, in accordance to an example embodiment of the invention.
FIG. 7 illustrates a graphical representation of Gas chromatography-mass spectrometry (GC-MS) Chromatogram of neem oil laser biodiesel, in accordance to an example embodiment of the invention.
FIGs. 8A-8D illustrate graphical representations depicting the influence of various parameters on biodiesel yield from both neem oil and laser-treated neem oil, in accordance to an example embodiment of the invention.
FIG. 9 illustrates a graphical representation depicting the biodiesel yield percentage over five catalyst runs, in accordance to an example embodiment of the invention.
Detailed invention disclosure:
Various embodiments of the present invention will be described with reference to the accompanying drawings. Wherever possible, the same or similar reference numerals are used in the drawings and the description to refer to the same or similar parts or steps.
The present disclosure has been made with a view towards solving the problem with the prior art described above, and it is an object of the present invention to provide a method for producing high-purity biodiesel from neem oil using laser pre-treatment and a CaO nanocatalyst to achieve enhanced efficiency and yield.
According to an exemplary embodiment of the invention, FIG. 1 refers to a flowchart 100 of a method for producing high-purity biodiesel from neem oil. The method improves the efficiency and yield of biodiesel production, thereby offering a sustainable and cost-effective alternative to traditional fossil fuels. The method enhances economic feasibility of biodiesel production and reduces the environmental impact associated with conventional diesel fuel. This method involves several stages, including pre-treatment of neem oil, transesterification reaction, and subsequent purification of the produced biodiesel to achieve high purity.
First, at step 101, the process begins with the pre-treatment of neem oil to enhance its reactivity and reduce the formation of unwanted by-products. Neem oil is subjected to a green laser with a wavelength of 532 nm for a duration of at least 30 minutes. This laser pre-treatment alters the physical and chemical properties of the neem oil, thereby making it more reactive in the subsequent transesterification reaction.
Next, at step 104, the free fatty acid (FFA) content of the neem oil is determined using a titration method. If the FFA content is greater than 2%, an acid esterification step is performed to reduce the FFA content to less than 2% at step 106. This step is crucial as high FFA content can lead to soap formation during the transesterification reaction, which can hinder the biodiesel production process.
Later, at step 108, the transesterification reaction is initiated by mixing the pre-treated neem oil with methanol and the synthesized CaO nanocatalyst in appropriate amounts. The mixture is maintained under controlled conditions, including temperature, duration, catalyst loading, and oil-methanol molar ratio at step 110. The optimal conditions for the transesterification reaction include a temperature range of 40 °C to 70 °C and a reaction duration of at least 60 to 150 minutes. The molar ratio of neem oil to methanol is varied within the range of 1:10 to 1:25, and the weight percentage of the CaO nanocatalyst is adjusted within the range of 0.5% to 1.25% to achieve maximum biodiesel yield.

After the transesterification reaction, the reaction mixture is allowed to separate into biodiesel and glycerol layers at step 112. The separation is achieved by transferring the reaction mixture to a separating funnel and allowing it to settle for a sufficient time duration to ensure complete separation. The biodiesel layer is then extracted from the separating funnel, thereby leaving behind the glycerol and other impurities.
Further, at step 114, the extracted biodiesel undergoes a cleaning process using an air bubble wash for a duration of 2 hours to ensure high purity. This process removes excess alcohol, water, and catalyst residues from the biodiesel. The cleaned biodiesel is then ready for use as a high-quality biofuel and stored for examination and analysis. The biodiesel yield is determined by applying an equation as follows.
Biodiesel yield (%)=(Volume of biodiesel)/(Volume of neem oil) X 100
According to an exemplary embodiment of the invention, FIG. 2 illustrates a schematic representation 200 of a synthesis process for the calcium oxide (CaO) nanocatalyst. In one embodiment herein, the calcium oxide (CaO) nanocatalyst used in the transesterification reaction is synthesized using a sol-gel method. First, at step 202, 11.81 g of calcium nitrate tetrahydrate (Ca(NO3)2·4H2O) is dissolved in 25 ml of ethylene glycol to create a solution. Later, at step 204, the solution is allowed to rest for a duration of at least 5 hr to form a gel. The gel is then filtered using distilled water and a filter paper. Later, at step 206, the filtered gel is dried in a hot air oven to obtain a dried gel, which is then ground into a fine powder using a mortar and pestle. Finally, at step 208, the powdered material is calcined in a muffle furnace at a temperature of at least 850°C for a duration of at least 1 hr to synthesize the CaO nanocatalyst.
In one embodiment herein, physico-chemical properties of the CaO nanocatalyst for the biodiesel production are represented in table 1.
Table 1:
Properties Calcium oxide Nano powder
Molecular formula CaO
Appearance White
Morphology Spherical
Density 3.34g/cc
Thermal conductivity 19.50W/m.K
Melting point 2613 oC
Boiling point 2850 oC

According to table 1, the nanocatalyst is calcium oxide, represented by the molecular formula CaO. This indicates that it consists of one calcium atom bonded with one oxygen atom. The calcium oxide nano powder is described as white in appearance. This suggests that it has a characteristically light color. The nanocatalyst exhibits a spherical morphology. This means that the individual particles of the catalyst have a roughly spherical shape. The density of the calcium oxide nano powder is 3.34 grams per cubic centimeter (g/cc). This value indicates the compactness of the material and how much mass is packed into a given volume.
In one embodiment herein, the thermal conductivity of the nano powder is 19.50 watts per meter-kelvin (W/m.K). This property measures how efficiently the material can conduct heat. A higher thermal conductivity implies better heat transfer capabilities. The melting point of calcium oxide is 2613 degrees Celsius (°C). This is the temperature at which the solid calcium oxide transitions into a liquid state. The boiling point of calcium oxide is 2850 degrees Celsius (°C). This is the temperature at which the liquid calcium oxide transforms into a gaseous state.
In one embodiment herein, the neem oil used in the method is produced by cold pressing raw neem seeds. This extraction process ensures that the oil retains its natural properties. The extracted neem oil is then heated to a temperature of at least 110±5 °C to remove any moisture present in the oil. After heating, the neem oil is filtered using a filter paper to remove impurities, thereby producing pure neem oil suitable for the transesterification reaction.
In one embodiment herein, the physico-chemical properties of neem oil and laser-treated neem oil for the biodiesel production are presented in table 2.
Table 2:
S. No Properties Neem oil Laser-treated neem oil
1 Physical state Liquid Liquid
2 Colour Brown Light brown
3 Kinematic viscosity@40 oC (cst) 23.54 22.38
4 Acid value(mg KOH/g) 8.77 9.18
5 Density (kg/m3) 0.875 0.875
6 Saponification value(mg KOH/gm) 184.5 189.12
7 Specific gravity 0.918 0.918

According to table 2, both neem oil and laser-treated neem oil exist in a liquid state at ambient conditions. This indicates that they are readily pumpable and can be easily handled in various processes, including biodiesel production. Neem oil is described as brown in color, while laser-treated neem oil appears light brown. This suggests that the laser treatment process has a slight bleaching effect on the oil, reducing its color intensity. Kinematic viscosity measures the resistance of a fluid to flow under gravity. At 40 °C, neem oil has a kinematic viscosity of 23.54 centistokes (cSt), whereas laser-treated neem oil exhibits a slightly lower viscosity of 22.38 cSt. This reduction in viscosity with laser treatment could potentially improve the flow properties of the oil.
In one embodiment herein, acid value indicates the amount of free fatty acids present in the oil. Neem oil has an acid value of 8.77 mg KOH/g, while laser-treated neem oil shows a slightly higher acid value of 9.18 mg KOH/g. This suggests that the laser treatment process might have led to a minor increase in free fatty acid content. Both neem oil and laser-treated neem oil have the same density of 0.875 kg/m³. This indicates that they have similar mass-to-volume ratios. Saponification value represents the amount of alkali required to saponify (convert) a specific amount of oil into soap. Laser-treated neem oil has a higher saponification value of 189.12 mg KOH/g compared to 184.5 mg KOH/g for neem oil. This suggests that laser-treated neem oil might have a higher content of triglycerides, which are the main components involved in biodiesel production.
In one embodiment herein, specific gravity is the ratio of the density of a substance to the density of water. Both neem oil and laser-treated neem oil have the same specific gravity of 0.918. This indicates that they are lighter than water. Therefore, the laser treatment process appears to have slightly reduced the color and viscosity of the oil while increasing its acid value and saponification value. These changes could potentially impact the biodiesel production process and the final properties of the resulting biodiesel.
In one embodiment herein, property analysis of the neem oil biodiesel with American Society for Testing and Materials (ASTM) standards are represented in table 3.
Table 3:
Properties Neem Oil Biodiesel NOLT
Biodiesel ASTM D6751 EN 14214 Diesel
Carbon Chain FAME C12-C22 FAME C12-C22 FAME
C12-C22 FAME
C12-C22 C9-C20
Density @ 30 °C 878 845 860-900 - 823-844
Kinematic Viscosity @ 40 °C 5.31 4.96 1.9-6.0 3.5-5.0 2.5-6.0
Calorific
Value (MJ/Kg) 38.4 39.3 37.7 >35 -
Cetane Number 49 49 >47 51 45-50
Flash Point 173 180 >93 >101 52
Fire Point 205 210 >130 - -
Cloud Point 16 18 -15-10 - -
Pour Point -4 -1 -15-16 - -8
Acid Value 0.6 0.44 <0.8 <0.50 -
Oxidation Stability (hrs) 6 5.5 3 8 -

In one embodiment herein, the table 3 compares the properties of neem oil biodiesel, NOLT biodiesel, and diesel fuel against ASTM D6751 and EN 14214 standards. This analysis is crucial for assessing the suitability of these biodiesels as alternative fuels. Both neem oil biodiesel and NOLT biodiesel consist primarily of fatty acid methyl esters (FAME) with carbon chain lengths ranging from C12 to C22, similar to the ASTM and EN standards. Their densities fall within the acceptable range for biodiesel according to ASTM D6751, thereby indicating appropriate fuel handling characteristics. However, their kinematic viscosities are slightly higher than the ASTM and EN limits, which might impact fuel atomization and engine performance. Both biodiesels exhibit higher calorific values than the ASTM minimum, suggesting good energy content.
In one embodiment herein, both biodiesels meet the cetane number requirements of ASTM D6751 and EN 14214, thereby ensuring good ignition quality and engine performance. Their flash and fire points significantly exceed the safety standards, making them safe to handle. Both biodiesels have cloud and pour points within the ASTM acceptable ranges, indicating their suitability for use in colder climates. However, their values are slightly higher than the EN 14214 limits, which might affect cold weather performance in some regions.
In one embodiment herein, the acid values of both biodiesels are lower than the ASTM and EN limits, thereby suggesting good fuel quality and reduced engine wear. Both biodiesels also meet the oxidation stability requirements of ASTM D6751, thereby ensuring long-term fuel storage stability. Overall, both neem oil biodiesel and NOLT biodiesel generally meet the ASTM D6751 standards for biodiesel, thereby indicating their potential as suitable alternative fuels.
In one embodiment herein, composition of Laser Neem Oil Methyl Ester (LNOME) are represented in table 4.
Table 4:
S.No Compounds Molecular formula Molecular wt Retention time Area %
1 9,12-Octadecadienoic acid (Z,Z)-, methyl ester C15H34O2 294 31.803 14.48
2 9-Octadecenoic acid, methyl ester, (E)- C16H36O2 296 31.973 13.95
3 Hexadecanoic acid, methyl ester C17H34O2 270 28.591 15.21
4 Methyl tetradecanoate C15H30O2 242 24.288 1.27
5 Methyl stearate C19H38O2 298 32.375 3.92
6 9-Octadecenoic acid, 12 hydroxy-, methyl ester, (Z)- C19H36O3 312 35.287 6.24
7 n-Hexadecanoic acid C16H32O2 256 29.338 3.87
8 Heneicosanoic acid, methyl ester C22H44O2 340 35.869 1.48
9 Hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl)ethyl ester C19H38O4 370 38.948 8.07
10 6-Octadecenoic acid, methyl ester, (Z)- C19H36O2 296 32.020 1.51
11 Tricyclo[20.8.0.0(7,16)]triacontane, 1(22),7(16)-diepoxy- C30H52O2 444 36.809 2.14
12 9-Octadecenoic acid (Z)-,2,3-dihydroxypropyl ester C21H40O4 356 41.770 20.66

According to table 4, the primary ingredients of LNOME are fatty acid methyl esters (FAME), which are derived from neem oil. 9,12-Octadecadienoic acid-(Z,Z)-, methyl ester is the most abundant FAME in the sample, constituting approximately 14.48% of the total composition. 9-Octadecenoic acid, methyl ester, (E)- comprises around 13.95% of the LNOME. Hexadecanoic acid, methyl ester accounts for about 15.21% of the total composition. Methyl stearate contributes approximately 3.92% to the LNOME. 9-Octadecenoic acid, 12-hydroxy-, methyl ester, (Z)- represents around 6.24% of the sample.
In one embodiment herein, n-Hexadecanoic acid, methyl ester constitutes around 3.87% of the LNOME. Heneicosanoic acid, methyl ester contributes about 1.48% to the sample. 6-Octadecenoic acid, methyl ester, (Z)- represents approximately 1.51% of the LNOME. 9-Octadecenoic acid (Z)-, 2,3-dihydroxypropyl ester is a significant component, thereby accounting for around 20.66% of the total composition. The composition of LNOME is primarily characterized by a diverse range of FAMEs, with 9,12-Octadecadienoic acid-(Z,Z)-, methyl ester being the most abundant. The presence of hydroxylated FAMEs and other minor compounds adds complexity to the fuel's properties. This detailed composition analysis provides valuable insights into the potential characteristics and performance of LNOME as a biodiesel fuel.
According to an exemplary embodiment of the invention, FIGs. 3A–3D refer to scanning electron microscope (SEM) images 300, 302, 304, and 306 of synthesized nanocatalyst at 5µm, 10µm, 20µm, and 100µm magnification, respectively. In one embodiment herein, the provided SEM images 300, 302, 304, and 306 present the morphology of the synthesized CaO nanocatalyst at varying magnifications of 500X, 2.5KX, 6KX, and 8KX. These SEM images 300, 302, 304, and 306 offer valuable insights into the catalyst's structural characteristics, which are crucial for understanding its catalytic performance. Based on the SEM images 300, 302, 304, and 306, the CaO nanocatalyst exhibits an irregular particle shape with a porous structure. The presence of pores and irregularities on the particle surface creates a larger surface area, which is beneficial for catalytic reactions. This increased surface area allows for more active sites to be exposed, thereby enhancing the catalyst's efficiency in interacting with reactant molecules.
Therefore, the SEM images 300, 302, 304, and 306 reveal a broad range of particle sizes within the catalyst sample. This variation in particle size contributes to the overall surface area and potentially influences the catalyst's activity. The presence of both smaller and larger particles can impact factors such as mass transfer and reaction kinetics. The combination of irregular particle shape, porous structure, and a wide range of particle sizes suggests that the CaO nanocatalyst has the potential for high catalytic activity. The increased surface area provided by these characteristics can facilitate efficient adsorption and interaction with reactant molecules, thereby leading to improved catalytic performance.
According to an exemplary embodiment of the invention, FIG. 4 refers to a graphical representation 400 depicting an X-ray diffraction (XRD) pattern of the synthesized CaO nanocatalyst. In one embodiment herein, the provided XRD pattern offers insights into the crystal structure and size of the synthesized CaO nanoparticles. The distinct peaks observed in the pattern correspond to the diffraction of X-rays from specific crystal planes within the CaO lattice. The prominent peaks in the XRD pattern are located at approximately 18.027°, 28.649°, 34.071°, 47.107°, 50.769°, 54.329°, 62.577°, and 59.356°. These peaks align with the characteristic diffraction patterns of calcium oxide (CaO) nanoparticles. The crystallite size of the CaO nanoparticles was determined using the Debye-Scherer equation. By analyzing the peak broadening and applying this equation, the average crystallite size was calculated to be 47.60 nm, with a range of 24 to 79 nm.
Therefore, the XRD pattern confirms the successful synthesis of CaO nanoparticles with a predominantly crystalline structure. The calculated crystallite size provides valuable information about the size distribution of the nanoparticles, which can influence their properties and potential applications. While the XRD pattern reveals the crystalline nature and size of the CaO nanoparticles, further characterization techniques, such as transmission electron microscopy (TEM) or scanning electron microscopy (SEM), would be necessary to confirm the particle morphology and size distribution. Additionally, investigating the specific surface area and porosity of the nanoparticles could provide additional insights into their potential catalytic activity.
According to an exemplary embodiment of the invention, FIGs. 5A and 5B refer to graphical representations 500 and 502 depicting Fourier Transform Infrared (FTIR) spectra of neem oil and laser-treated neem oil. In one embodiment herein, the graph 500 presents the FT-IR spectra of neem oil before and after laser pretreatment. Prominent peaks corresponding to the OH stretching of carboxylic acids are observed between 2922 cm?¹ and 2853 cm?¹. A characteristic peak associated with the ester C=O stretching appears at 1743 cm?¹. Additionally, the region spanning 1460 cm?¹ to 1385 cm?¹ corresponds to the C-H bending in the alkane methylene group.
In one embodiment herein, the graph 502 illustrates the FT-IR spectra of neem oil methyl ester (NOME) and laser-pretreated neem oil methyl ester (LNOME) obtained through transesterification. The bands between 2939 cm?¹ and 2831 cm?¹ represent the prominent peaks of the OH stretching of carboxylic acids. Notably, the characteristic peak at 1743 cm?¹, indicative of ester C=O stretching, is absent in both NOME and LNOME, suggesting successful conversion during transesterification. The region between 1452 cm?¹ and 1345 cm?¹ corresponds to the C-H bending in the alkane methylene group.
According to an exemplary embodiment of the invention, FIGs. 6A–6D refer to graphical representations 600, 602, 604, and 606 of Hydrogen nuclear magnetic resonance (H-NMR) spectra for neem oil methyl ester (NOME) and laser-treated neem oil methyl ester (LNOME) conversion. In one embodiment herein, the provided H-NMR spectra offer valuable insights into the conversion of neem oil and laser-pretreated neem oil into their respective methyl esters (NOME and LNOME). The prominent peaks at 3.19 ppm for NOME and 3.134 ppm for LNOME correspond to the methoxy (OCH3) protons of the methyl esters. The presence and intensity of these peaks indicate the successful conversion of triglycerides to methyl esters. The signals at 1.123 ppm (NOME) and 1.059 ppm (LNOME) are attributed to the protons of the a-carbon CH2 groups in the fatty acid derivatives. These peaks further support the formation of methyl esters.
In one embodiment herein, the peaks at 5.153 ppm and 5.086 ppm represent the olefinic hydrogens present in the unsaturated fatty acid chains. The presence of these peaks confirms the unsaturated nature of the fatty acid components in both NOME and LNOME. The relative intensities of the methoxy group peaks (3.19 ppm and 3.134 ppm) compared to the a-carbon CH2 group peaks (1.123 ppm and 1.059 ppm) can be used to estimate the conversion yield of neem oil to methyl esters. A higher ratio of methoxy to a-carbon CH2 peak intensities indicates a higher conversion efficiency.
According to an exemplary embodiment of the invention, FIG. 7 refers to a graphical representation 700 of Gas chromatography-mass spectrometry (GC-MS) Chromatogram of neem oil laser biodiesel. The provided GC-MS chromatogram presents a visual representation of the components present in the biodiesel sample. The x-axis represents retention time, indicating the time taken for different compounds to elute from the GC column. The y-axis represents the total ion current (TIC), a measure of the overall ion intensity detected by the mass spectrometer. Each peak in the chromatogram corresponds to a different compound in the sample. The chromatogram displays numerous peaks, suggesting the presence of multiple components in the biodiesel sample. This is consistent with the complex nature of biodiesel, which is typically a mixture of fatty acid methyl esters.
In one embodiment herein, the variation in peak heights indicates differences in the abundance of each component. Some peaks are more prominent than others, thereby suggesting that certain compounds are present in higher concentrations. The retention times of the peaks can provide information about the molecular weight and polarity of the compounds. By comparing the retention times to known standards or library data, it is possible to identify the specific components. In one embodiment herein, the information provided in Table 4 aligns with the GC-MS chromatogram. The three main components identified in Table 4 (methyl stearate, hexadecanoic acid, and 9-octadecenoic acid (Z)-methyl ester) are likely represented by some of the prominent peaks in the chromatogram.
According to an exemplary embodiment of the invention, FIGs. 8A-8D refer to graphical representations 800, 802, 804, and 806 depicting the influence of various parameters on biodiesel yield from both neem oil and laser-treated neem oil. In one embodiment herein, transesterification is employed to produce biodiesel by reacting an alcohol with a catalyst and triglycerides in a reactor. The process involved separating the products and washing the glycerol and methyl ester. During the optimization phase of this study, several variables were adjusted to enhance biodiesel yield.
In one embodiment herein, the transesterification reactions can occur at different temperatures depending on the catalyst and oil used. The optimal temperature range for the process is identified as 40 to 70°C, with neem oil biodiesel yielding the best results at 50°C, as illustrated in FIG. 8A. Increasing the reaction temperature led to a higher biodiesel yield due to a significant acceleration in the reaction rate. However, at 60°C, the pyrolysis of some components caused a reduction in conversion for the neem oil laser-treated biodiesel, negatively impacting the transesterification reaction.
In one embodiment herein, allowing sufficient reaction time is crucial for the complete conversion of triglycerides into biodiesel, ensuring thorough mixing of all reactants. By keeping other variables constant and adjusting the reaction time between 60 and 150 minutes, the study determined that the maximum FAME (Fatty Acid Methyl Ester) conversion for both feedstocks was achieved after 90 min. FIG. 8B illustrates the negative correlation between the produced glycerol and biodiesel, which ultimately reduces biodiesel yield.
In one embodiment herein, this study also explored the impact of catalyst loading on the transesterification reaction, using the synthesized CaO nanocatalyst. Conversion increased proportionally with the catalyst concentration, indicating that more active sites were available for the transesterification reaction. The active sites on the catalyst facilitated the conversion of methanol into the more reactive methoxide ion, resulting in higher conversion rates. The maximum output of neem oil biodiesel was achieved with 1 wt% catalyst loading, as shown in FIG. 8C.
During the experimentation, the oil-to-methanol ratio varied from 1:10 to 1:25 while keeping the temperature, catalyst loading, and reaction duration constant. The study found that a 1:20 oil-to-methanol ratio was optimal for the conversion of neem oil to biodiesel. Increasing the amount of methanol generally led to a higher volume of biodiesel due to the reversible nature of the reaction. However, as shown in FIG. 8D, there was minimal difference in yield between the ratios tested. Excessive methanol, on the other hand, could lead to an excess volume of liquid, which would decrease the chances of triglycerides contacting the catalyst, thus reducing the conversion efficiency.
According to an exemplary embodiment of the invention, FIG. 9 refers to a graphical representation 900 depicting the biodiesel yield percentage over five catalyst runs. Triglycerides can be transesterified into glycerol and biodiesel more efficiently with the use of nanocatalysts, which have become crucial in biodiesel production. However, fouling or catalyst deactivation can eventually reduce the nanocatalyst's lifespan and efficacy. Regenerating the nanocatalyst offers a viable way to enhance process efficiency and extend catalyst life. The study observed a decrease in yield over repeated cycles, which can be attributed to deactivation, leading to the loss of active sites and the potential formation of undesirable by-products that may deposit on the catalyst surface. As illustrated in FIG. 9, indicate that this CaO nanocatalyst is reusable for up to five cycles.
The transesterification process of neem oil, catalyzed by CaO derived from calcined hydrated lime, demonstrated exceptional water tolerance. This is because the OH groups produced by water accelerate the formation of the methoxide anion. However, when the water concentration in the reaction exceeded 5 weight percent, soap formation was triggered, leading to a decrease in FAME yield to 65%. The FAME yield following laser pretreatment exhibited a similar pattern.
In one embodiment herein, the provided graph 900 illustrates the biodiesel yield percentage over five catalyst runs. It appears that the catalytic activity decreases with each subsequent run. The first two catalyst runs demonstrate exceptionally high biodiesel yields, reaching 97% and 94% respectively. This indicates the high efficiency of the fresh nanocatalyst in converting triglycerides to biodiesel. A gradual decrease in biodiesel yield is observed in the following runs, with yields dropping to 89%, 86%, and 75% for runs 3, 4, and 5 respectively. This trend suggests a decline in the catalyst's activity over time.
Numerous advantages of the present disclosure may be apparent from the discussion above. In accordance with the present disclosure, the method is disclosed for producing high-purity biodiesel from neem oil using laser pre-treatment and a CaO nanocatalyst to achieve enhanced efficiency and yield. The method enhances the efficiency and yield of biodiesel production from neem oil through the integration of laser pre-treatment, which modifies the physical and chemical properties of neem oil to improve its reactivity. The method utilizes the CaO nanocatalyst in the biodiesel production, thereby leveraging high surface area and unique catalytic properties of the CaO nanocatalyst to accelerate the transesterification reaction and reduce the amount of catalyst required.
The proposed method minimizes the environmental impact of biodiesel production by reducing the energy requirements and chemical waste associated with traditional methods, thereby offering a more sustainable and eco-friendly approach. The method provides a cost-effective solution for biodiesel production that enhances the economic feasibility of using neem oil as a feedstock, thereby making biodiesel a more viable alternative to conventional diesel fuels. The method ensures consistent high-purity biodiesel output, thereby improving the overall quality and performance of the biodiesel produced from neem oil.
The proposed method develops a scalable and commercially viable biodiesel production that can be easily adapted and implemented in various production settings, from small-scale to large-scale operations. The method contributes to the reduction of greenhouse gas emissions and dependence on fossil fuels by providing an efficient method for producing renewable biodiesel from neem oil. The method improves the overall sustainability of biodiesel production by utilizing a renewable and readily available feedstock, neem oil, and optimizing the production process to minimize waste and energy consumption.
It will readily be apparent that numerous modifications and alterations can be made to the processes described in the foregoing examples without departing from the principles underlying the invention, and all such modifications and alterations are intended to be embraced by this application.

, Claims:CLAIMS:
I / We Claim:
1. A method for producing high-purity biodiesel from neem oil, comprising:
pre-treating the neem oil using a green laser with a wavelength of 532 nm for a duration of at least 30 min to enhance reactivity of the neem oil and reduce the formation of unwanted by-products;
determining free fatty acid (FFA) content of the neem oil using a titration method;
performing acid esterification to reduce the FFA content if it is greater than at least 2%;
mixing the laser treated neem oil with methanol and a calcium oxide (CaO) nanocatalyst in appropriate amounts to initiate a transesterification reaction, thereby obtaining a reaction mixture;
maintaining the reaction mixture under controlled conditions of temperature, duration, catalyst loading, and oil-methanol molar ratio;
allowing the reaction mixture to separate into biodiesel and glycerol layers; and
cleaning the biodiesel for a time period of at least 2 hr using an air bubble wash process to remove excess alcohol, water, and catalyst residues, thereby producing the high-quality biodiesel.
2. The method as claimed in claim 1, wherein the neem oil is produced by:
cold pressing raw neem seeds to extract the neem oil;
heating the extracted neem oil to a temperature of at least 110±5 °C to remove moisture present in the neem oil; and
filtering the heated neem oil to remove impurities using a filter paper, thereby producing the neem oil for the transesterification reaction.
3. The method as claimed in claim 1, wherein the CaO nanocatalyst is synthesized using a sol-gel method, wherein the sol-gel method comprises:
dissolving at least 11.81 g of calcium nitrate tetrahydrate (Ca(NO3)2·4H2O) in 25 ml of ethylene glycol to create a solution;
allowing the solution to rest for a time period of at least 5 hr to form a gel;
filtering the gel using distilled water and a filter paper;
drying the filtered gel in a hot air oven at a temperature to obtain a dried gel;
grinding the dried gel into a fine powder using a mortar and pestle; and
calcining the powdered material in a muffle furnace at a temperature of at least 850° C for a time period of at least 1 hr.
4. The method as claimed in claim 1, wherein the transesterification reaction is carried out at a temperature that varies between 40 °C and 70 °C.
5. The method as claimed in claim 1, wherein the transesterification reaction is conducted for a time period of at least 60 to 150 min.
6. The method as claimed in claim 1, wherein the transesterification reaction is optimized by varying a molar ratio of neem oil to methanol within the range of at least 1:10 to 1:25 and adjusting weight percentage of the CaO nanocatalyst within the range of at least 0.5% to 1.25% to achieve maximum biodiesel yield.
7. The method as claimed in claim 1, wherein the separation of the biodiesel from the reaction mixture is achieved by:
transferring the reaction mixture to a separating funnel;
allowing the reaction mixture to settle for a time duration sufficient to separate the biodiesel from glycerol and other impurities; and
extracting the biodiesel layer from the separating funnel, thereby leaving behind the glycerol and impurities.