Biodiesel Synthesis from Date Seed Oil Using Camel Dung as a Novel Green Catalyst: An Experimental Investigation

Abstract

Biodiesel is seen as more environmentally benign than petroleum-based fuels. It is also cheaper and capable of creating cleaner energy, which has a good impact on increasing the bioeconomy. An investigation was conducted on a novel heterogeneous catalyst system utilized in the synthesis of eco-friendly biodiesel from date seed oil, a non-edible feedstock obtained through the calcination of desiccated camel manure at varying temperatures. X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) analysis, and scanning electron microscopy (SEM) were utilized to characterize this catalyst. As a result of raising the calcination temperature, the results showed that the pore size of the catalyst decreased. The biodiesel production was optimized to be 86% by using the transesterification method. The optimal reaction parameters included a catalyst with 4% loading, a molar ratio of 1:8 between date seed oil and ethanol, and a temperature of 75 °C for a reaction period of three hours. The confirmation of FAME generation was achieved by gas chromatography–mass spectrometry (GC–MS). The fuel qualities of fatty acid ethyl ester are in accordance with ASTM, suggesting that it is a suitable alternative fuel option. Utilizing biodiesel derived from waste and untamed resources to establish and execute a more sustainable and ecologically conscious energy plan is praiseworthy. The adoption and integration of green energy practices could potentially yield positive environmental outcomes, thereby fostering enhanced societal and economic development for the biodiesel sector on a broader scale.

1. Introduction

Biodiesel, being a sustainable energy source, has several characteristics that make it suitable for use as an automotive fuel. Biodiesel exhibits a lower level of pollution compared to petroleum diesel due to its absence of sulfur content and significantly reduced carbon dioxide emissions. Consequently, the use of biodiesel contributes to the mitigation of global warming and the preservation of fossil fuel reserves [1,2,3]. One additional benefit of biodiesel fuel is its ability to be blended with different energy supplies. Most conventional biodiesels are manufactured using edible vegetable oil. Because of this, biodiesel becomes economically unattractive, as biodiesel producers face increased competition from the edible oil industry. Therefore, the biggest challenge for the commercialization for biodiesel is the high cost of feedstock for biodiesel manufacturing. Consequently, research has endeavored to identify sustainable and cost-effective alternatives for feedstock.

In recent years, a few studies have examined non-edible and cost-effective alternatives to animal lipids, waste cooking oil (WCO) [4], yellow or brown grease, and sewage oil like fats, oils, and grease (FOG) for biodiesel production. Waste of this nature is easily obtainable as municipal and industrial byproducts. The use of date seed oil as a feedstock for biodiesel production is a viable option for addressing the issue of waste disposal associated with this kind of residue. Date seeds are mostly considered solid waste, with just a small portion being used as animal feed for species such as chickens, camels, sheep, and cattle [5]. Significant quantities of date seeds may be obtained from date processing facilities and related sectors, either via direct or indirect means [6]. Furthermore, the date palm is mostly distributed in the dry and hot regions of southern Asia and northern Africa. Based on the statistics data published by the Food and Agriculture Organization (FAO), the global production of dates in 2010 amounted to 7.85 million tons. Saudi Arabia is one of the top ten nations in terms of date production, based on reported figures, with a production of 10,78,300 tons [6].

Multiple methods exist to produce biodiesel, including esterification, interesterification, and transesterification. Esterification is a commonly used method to produce biodiesel using oil feedstock with high acid values. Interesterification has the potential to generate biodiesel alongside several other valuable by-products, rather than glycerol. Transesterification, however, is widely recognized as the predominant and favored technique to produce biodiesel. The procedure yields biodiesel of exceptional grade. The simplicity of the production reaction contributes to the comparatively lower total operating cost of this biodiesel production technique in comparison to other methods. Alcohol is an additional feedstock required to produce biodiesel using the transesterification method.

The catalysts used in the manufacture of biodiesel are classified into three distinct categories: homogeneous, heterogeneous, and enzyme based. Typically, homogeneous catalysts, such as sodium hydroxide (NaOH) and potassium hydroxide (KOH), are employed [7]. Nevertheless, it is important to acknowledge that this catalyst does possess some limits. A homogeneous catalyst is incapable of being separated after the reaction, thereby limiting its utility to a single use. The formation of soap because of water washing after the reaction is a challenge that is linked to the use of a homogeneous catalyst. However, it is worth noting that a heterogeneous catalyst can surpass these constraints. Both heterogeneous base catalysts [8] and heterogeneous acid catalysts exist [9]. Heterogeneous catalysts are manufactured from a variety of waste materials, including shells [10], ash from biomass combustion [9], biochar [11], bones from slaughtered animals [1,2,3], and activated carbon [12].

Camel dung tends to be more alkaline because the digestive systems of herbivores are designed to break down plant material, which is often more alkaline in nature. Camel dung is a readily available and abundant resource in regions where camels are prevalent, like in the Empty Quarter desert in Saudi Arabia. This makes them a sustainable source of catalyst material, reducing the need for traditional chemical catalysts that may be less eco-friendly. Furthermore, utilizing camel dung as a catalyst repurposes a waste material that would otherwise need to be managed or disposed of. This contributes to waste reduction and minimizes the environmental impact. To the best of our knowledge, this is the first work that used calcined camel dung as a catalyst for biodiesel production. Therefore, this study aimed to investigate the feasibility of utilizing calcined camel dung, as an abundant and underutilized biomass resource, as a cost-free alternative catalyst for the transesterification process to produce biodiesel from date seed oil. This catalyst was calcined at different temperatures (600, 800, and 1000 °C), and the properties of the resulting catalyst were found to be dependent on the calcination temperature. Furthermore, the investigation of the catalyst included the use of X-ray diffraction (XRD), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX), and Brunauer–Emmett–Teller (BET) methods. Utilizing the ASTM6751 standards [13], the biodiesel product’s suitability for use as a fuel was evaluated. The production of biodiesel from date seed oil is both economically viable and does not compromise food security. In addition to reducing greenhouse gas emissions, it offers a cost-effective substitute for fossil fuels. Consequently, the objective of this study was to ascertain the economic advantages that arise from the transformation of refuse materials into products that offer added value.

2. Results and Discussion

2.1. Characteristic of Date Seeds Oil

The principal physicochemical parameters of the selected date seed oil were determined utilizing established methodologies (

Table 1. Physico-chemical properties of date seed oil.

Property	Unit	Measured Value
Kinematic viscosity at 40 °C	Cst	40
Acid value	mg KOH/g oil	1.45
Flash point	°C	245

).

The phytochemical analysis (

Table 2. Preliminary phytochemical screening of 80% methanol extract of camel feces.

Test		80% Ethanol	Crude Powdered
Flavonoids	Mg/H2SO4	++	++
Alkaloids	Dragendorffs	+++	++
Saponins	Foam	-	-
Tannins	Ferric chloride	-	-
Terpenes and sterol	Salkowski	+++/+++	Not detect
Sugar	Fehling’s	+	+
Amino acids	Ninhydriene	+	+
Proteins	Buiret	++	+
Ph	pH meter	8.5	-

+++ = high amount; ++ = moderate amount; + = low amount; - = not detectable.

) of camel dungs revealed that the crude powdered and methanolic extracts of camel dung were rich in alkaloids (+2, +3) flavonoids (+2, +3), terpenoids, and steroids (0, +3); while saponins were absent. It also showed low amounts of sugar, amino acids, and protein (+1). Furthermore, heat treatment at 1000C shows high amounts of Ca (25.71) and oxygen (42.05), a moderate amount of P (11.92), and low amounts of Si (10.03). Also, the sample was heat treated at 100 °C, shows high amounts of Ca (23.7), moderate amounts of oxygen (42.78) and Si (16.37), and low amounts of Mg (7.55) and P (6.82). Very low amounts of K and Na were observed in both samples. Furthermore, low amounts of Bacillus subtilis spores were detected in fecal samples. Also, the detected pH of camel dung was 8.6.

2.2. Catalyst Characterizations

2.2.1. BET

Catalyst samples calcined at several temperatures are shown in

Table 3. BET analysis.

Camel dung Catalyst at Different Calcination Temperature	Surface Area (m2/g)	Pore Size (nm)	Pore Volume (cm3/g)
100	28.0316	2.0842	2.9211 × 10−2
400	29.3410	2.0082	2.6210 × 10−2
600	56.3110	1.9812	8.9271 × 10−2
800	177.6980	1.8977	16.8610 × 10−2

according to their specific surface area, specific pore volume, and average pore diameter. Catalysts calcined at higher temperatures had a better crystalline order and higher surface area, as shown by XRD (Figure 1). In addition, the pore size of the catalyst calcined at 800 °C was found to be smaller than that of other catalysts. The pore sizes of microporous materials are shown (Table 3).

2.2.2. XRD Analysis

Figure 1 shows the X-ray powder diffraction analysis of camel dung samples treated at different temperatures. Three crystalline minerals were detected, two of which were forms of silica quartz and cristobalite; the third mineral was lewisite. The presence of these minerals was confirmed by EDX elemental analysis. The intensity of the two cristobalite phase peaks at 2Ɵ of 22.05° and 31.47° was noted, and the content of the more amorphous cristobalite phase increased relative to the more crystalline quartz phase. It is clear from the figure that the degree of crystallinity decreased with increasing sintering temperature, which ended with amorphization at 1000 °C. The decrease in crystallinity with rising temperature is corroborative with the surface area, pore size, analysis, and catalytic activity of the obtained catalysts. Table 3 shows the increase in surface area with increasing amorphization, and that pore size decreased with increasing sintering temperature due to the migration of silica particles which led to the closer packing of particles.

2.2.3. SEM/EDX Analysis

A scanning electron microscope (SEM) (National Research Center, Giza, Egypt) micrograph of the camel dung sample treated at 800 °C is presented in Figure 2a. The partial hexagonal crystals of quartz mineral and octahedral crystals of cristobalite mineral are indicated by arrows. The presence of quartz and cristobalite minerals was confirmed by the XRD analysis shown in Figure 1, and the energy dispersive X-ray (EDX) (National Research Center, Giza, Egypt) analysis in Figure 2b also confirms this. The image shows particles with platy, eroded rod, rectangular, and prismatic shapes of different sizes. From the image, the average surface area of the particles was estimated to be about 1.2 × 0.6 µm. The average content levels of different chemical elements obtained by EDX are presented in

Table 4. The content of different elements of the camel dung sample treated at 800 °C.

Error %	Net Int.	Atomic %	Weight %	Element
70.82	1.81	2.15	2.21	NaK
15.7	11.25	6.92	7.55	MgK
8.93	33.82	12.98	16.37	SiK
17.04	10.74	4.91	6.82	P K
70.05	0.92	0.32	0.56	K K
8.58	31.6	13.17	23.7	CaK
0	0	59.28	42.05	Oxygen

. This confirmed the presence of lewisite mineral elements which appear in the XRD in Figure 1. The high atomic % of oxygen in Table 4 indicates the presence of all metals as oxides and oxysalts.

2.3. Catalytic Activity in Transesterification

The Influence of Calcination Temperature on the Activity of the Catalyst

It is important to acknowledge that the primary objective of calcination is the removal of secondary crystalline phases, hence facilitating the advancement of the desired phase. The impact of activation temperature on transesterification activity was investigated within the temperature range of 600–1000 °C for the chosen feedstock, as demonstrated in

Table 5. The impact of varying calcination temperatures on the catalytic activity of camel dung.

Temperature of Calcination (°C)	Biodiesel Yield (%)
Uncalcined	-
600	65
800	86
1000	80

Reaction conditions: catalyst loading of 4 wt%, reaction time 3 h, reaction temperature 75 °C, oil to ethanol molar ratio 1:8.

. The use of calcination on the catalyst facilitates the removal of secondary phases, leading to enhanced crystallinity and particle compaction. The findings of this study indicated a direct relationship between the increase in calcination temperature of waste camel dung-derived material and the corresponding rise in biodiesel conversion. The catalyst that underwent calcination at 800 °C exhibited the most significant catalytic activity when compared to other catalysts. The catalysts subjected to calcination at a temperature of 800 °C (referred to as C800) exhibited significant catalytic activity, perhaps attributed to the presence of an ideal quantity of active basic sites on the catalyst’s surface. The surface area magnitude of a catalyst plays a crucial role in influencing the accessibility of reactants to the active sites. Consequently, it directly impacts the catalyst’s activity and efficacy in the transesterification process. As a result, the C800 catalyst was chosen to enhance the properties of biodiesel. Moreover, according to the basicity values shown in

Table 6. The influence of calcination temperature on the basicity of the catalysts.

Calcination Temperature (°C)	Basicity (mmol/HCl)
600	7
800	8.3
1000	7.8

Reaction conditions: catalyst loading 4 wt%, reaction time of 3 h, reaction temperature of 75 °C, oil-to-ethanol molar ratio of 1:8.

, the catalyst calcined at a higher temperature exhibits a greater level of basicity in comparison to the catalysts calcined at lower temperatures. The greatest basicity value observed was 8.3 mmol/HCl when the catalyst was calcined at a temperature of 800 °C. Subsequently, a decrease in basicity was observed, with the value dropping from 8.3 to 7.8 mmol/HCl when the temperature of catalyst calcination was above 800 °C. This reduction in basicity may be attributed to the accelerated sintering rate of the catalyst at higher calcination temperatures, ultimately resulting in the suppression of its basicity. Based on the findings derived from the above characterization outcomes, it has been determined that the catalyst exhibited a significantly enhanced level of efficiency when the calcination temperature was elevated to 800 °C. Consequently, the catalyst was chosen for further investigation.

2.4. Effect of Ethanol–Oil Molar Ratio

Date seeds’ oil-to-ethanol molar ratio is a very significant parameter in the process of transesterification. Insufficient or excessive quantities of ethanol in a chemical process result in a diminished output of biodiesel. The impact of the ethanol-to-oil molar ratio on the production of biodiesel may be seen in Figure 3. The molar ratios of ethanol to date seed oil used in the transesterification process ranged from 2:1 to 10:1. The data shown in Figure 3 clearly indicate that a molar ratio of 1:1 led to suboptimal biodiesel production and incomplete reaction, characterized by an excess of feedstock, perhaps due to an insufficient amount of ethanol in the reaction mixture. An upward correlation between the ratio of reactants and the yield was seen until a ratio of 8:1 was attained. At this juncture, the excess ethanol present in the mixture caused a modification in the kinetics of the reaction, leading to an enhanced interaction between the reactants and a higher conversion rate to biodiesel. Nevertheless, when the molar ethanol-to-oil ratio exceeded 8:1, there was a decrease in biodiesel production due to complications in the subsequent stages of the process. This hindered the separation of the desired product from the by-products, posing obstacles. The transesterification process tends to undergo a reverse reaction, leading to the formation of reactants rather than the desired biodiesel product. The reversible nature of the transesterification process has been identified as the cause of this outcome [14]. Consequently, the optimal ratio of reactants was determined to be 8:1.

2.5. Effect of Reaction Temperature

It is apparent that the quantity of biodiesel generated during a transesterification process is impacted by temperature. As can be seen in Figure 4, the progressive transformation of date seed oil into biodiesel took place at reaction temperatures ranging from 50 to 80 °C. At a reaction temperature of around 75 °C, biodiesel production was approximately 86% of its maximum. An increase in temperature facilitates the ascent of the substrate beyond the barrier of activation energy [15]. Due to the reduction in the viscosity of date seed oil, the yield of biodiesel typically increases with the temperature of the reaction [16]. Lower yields of biodiesel were obtained at reaction temperatures below or above 75 °C. Because of the oil’s high viscosity at lower temperatures, an insufficient reaction temperature caused insufficient mixing among the reactants. Nevertheless, according to Kirubakaran and his group [17], increasing the reaction temperature above the optimal level does not result in an improvement in the biodiesel yield. According to Ngige and coworkers [18], an increase in reaction temperature leads to a heightened rate of saponification in triglycerides, resulting in a decrease in the generation of biodiesel. Furthermore, Baskar et al. [19] observed a reduction in the polarity of methanol resulting from the excessive heating of reactants in a transesterification process. This loss in polarity is identified as a contributing factor to the limited production of biodiesel at elevated reaction temperatures [19]. Furthermore, as ethanol has a low boiling point, it may not have been as available in the reaction mixture. This is because ethanol would have been constantly condensing, even though the biodiesel output was lower at 80 °C.

2.6. Effect of Reaction Time

Typically, the production of biodiesel exhibits an augmented yield in correlation with the duration of the reaction. The optimal response time for a transesterification process is contingent upon several factors, including the specific feedstock, the catalyst used, and its concentration. Figure 5 demonstrates the influence of response time on the transesterification process. The highest achievable biodiesel production was obtained after a reaction period of three hours. According to a previous study [19], the biodiesel yield undergoes a significant reduction due to the reversible reaction of the transesterification process after the ideal reaction time. Additionally, a longer reaction time may result in the hydrolysis of esters and the formation of additional fatty acids, thereby reducing the yield of biodiesel.

2.7. Effect of Catalyst Loading

The concentration of a catalyst has a significant impact on the production of biodiesel. Therefore, a predetermined loading spectrum was used to evaluate its effect. The production of biodiesel at a catalyst loading of 1 wt% resulted in a comparatively lower yield (Figure 6). This may be attributed to a decrease in the number of active sites available, leading to an incomplete conversion of the reactants. The increase in catalyst concentration resulted in an improvement in the yield of biodiesel. This trend was seen consistently throughout the whole range of concentrations and was attributable to the greater availability of active sites during the reaction. Nevertheless, there was a noticeable decline in the production of biodiesel, ranging from 4 to 7.5 wt%. One possible explanation for this phenomenon is that higher catalyst quantities, exceeding the average value, can result in the increased viscosity of the transesterification reaction product. This viscosity tends to hinder the mass transfer process within the liquid (oil/alcohol/solid (catalyst)) structure, ultimately causing a decline in biodiesel yield once the optimal catalyst quantity has been surpassed. Moreover, the reduction in biodiesel production might also be attributed to an excessive presence of heterogeneous catalysts inside the reaction container. This surplus of catalysts may hinder the effective blending of reactants, thus resulting in a decline in the overall yield of biodiesel. The presence of larger catalyst loadings might also lead to mass transfer limits of reactants and products, which in turn may contribute to suboptimal biodiesel synthesis, and the increase in the viscosity of the mixture of reactants hinders the process of mixing and mass transfer, resulting in a reduction in the yield of biodiesel. Therefore, it was deduced that a catalyst loading of 4 wt% yielded the highest productivity for this reaction.

2.8. Characterization of Biodiesel

The fuel characteristics of the biodiesel produced were assessed using the American Society for Testing and Materials’ (ASTM’s) methodology, which is often used to determine biodiesel’s quality and adherence to established biodiesel criteria. The data shown in

Table 7. Biodiesel’s fuel qualities in ideal reaction circumstances.

Property	Unit	ASTM	Measured Value for Prepared Biodiesel
Density	kg/m3	860–894	887
Viscosity @40 °C	mm2/s	1.8–5.0	4.5
Acid number	mg KOH/g	≤0.45	0.5
Flash point	◦C	>120	136

demonstrate that the biodiesel generated exhibited fuel properties of superior quality, falling within the specified range outlined by the biodiesel standard.

The identification of fatty acid ethyl esters (FAMEs) in biodiesel was accomplished using gas chromatography–mass spectrometry (GC-MS) analysis.

Table 8. The identification of fatty acid ethyl esters (FAMEs) in biodiesel was accomplished using GC/MS.

Peak	RT	Name	Formula	Area	Area Sum %
1	5.153	1-Deoxy-d-mannitol	C6H14O5	352087.25	0.87
2	5.399	2,4-Nonadienal, (E,E)-	C9H14O	274831.72	0.68
3	7.676	Octadecane	C18H38	413310.22	1.02
4	7.779	2-Undecanone	C11H22O	192092.96	0.47
5	7.814	2,4-Dodecadienal, (E,E)-	C12H20O	557769.5	1.38
6	7.98	2,4-Decadienal, (E,E)-	C10H16O	1002522.2	2.47
7	8.924	Heptacosane	C27H56	121366.81	0.3
8	9.181	Hexadecane, 2,6,10,14-tetramethyl-	C20H42	649182.3	1.6
9	9.33	Phenol, 2,4-bis(1,1-dimethylethyl)-	C14H22O	176278.49	0.43
10	9.513	Heptadecane, 2,6,10,15-tetramethyl-	C21H44	243331.52	0.6
11	9.645	Dodecanoic acid	C12H24O2	8048132.3	19.84
12	9.919	Dodecanoic acid, ethyl ester	C14H28O2	3078485.4	7.59
13	10.829	Dodecanoic acid, propyl ester	C15H30O2	181963.67	0.45
14	11.104	Eicosane, 10-methyl-	C21H44	495021	1.22
15	11.619	Tetradecanoic acid	C14H28O2	3417453.9	8.43
16	12.099	Tetradecanoic acid, ethyl ester	C16H32O2	1279835.7	3.16
17	13.49	Didodecyl phthalate	C32H54O4	115186.31	0.28
18	13.684	Di-n-decylsulfone	C20H42O2S	109503.95	0.27
19	14.4	Eicosane	C20H42	463845.71	1.14
20	14.995	Normal Hexadecanoic acid	C16H32O2	2389652.8	5.89
21	15.189	Tetradecane, 2,6,10-trimethyl-	C17H36	175242.7	0.43
22	15.67	Hexadecanoic acid, ethyl ester	C18H36O2	874532.69	2.16
23	18.508	Oleic Acid	C18H34O2	10618341	26.18
24	18.886	Octadecanoic acid	C18H36O2	385398.68	0.95
25	18.96	9,12-Octadecadienoyl chloride, (Z,Z)-	C18H31ClO	331658.8	0.82
26	19.063	Ethyl Oleate	C20H38O2	2646888.7	6.53
27	20.808	Butyl 9-tetradecenoate	C18H34O2	195625.04	0.48
28	25.174	Phenol, 2,2′-methylenebis [6-(1,1-dimethylethyl)-4-methyl-	C23H32O2	1768548.2	4.36

provides a comprehensive description of the fatty acid ethyl esters and other associated products, offering a more detailed analysis and elucidation of their characteristics and properties. This research successfully identified all the anticipated fatty acid ethyl esters, which are known to be significant constituents of biodiesel.

3. Materials and Methods

The transesterification reaction is consistently influenced by the reaction parameters. To maximize biodiesel production, it is crucial to identify optimal conditions for the transesterification process. In this study, four distinct aspects of transesterification were investigated: the molar ratio of oil to ethanol, which ranged from 1:3 to 1:9; the catalyst concentration, which ranged from 1 to 7 wt%; the reaction temperature, which ranged from 60 to 85 °C; the reaction duration, which ranged from 1 to 4 h. A manufacturing plant for date oil is situated in Dammam, Saudi Arabia, and it was the source of the date oil supply in this study.

3.1. Preparation and Characterization of the Catalyst

The desiccated camel dung was subjected to calcination in a muffle furnace within a temperature range of 600 to 1000 °C, with a heating rate of 10 °C/min, for a duration of 4 h (Figure 7). Subsequently, the calcined material was stored in a hermetically sealed glass enclosure. Several analytical techniques, such as X-ray diffraction (XRD) (Bruker D8 Advance, Bruker, Rheinstetten, Karlsruhe, Germany). (Operated at 40kv and 40mA using CU Ka radiation 1.54060), Brunauer–Emmett–Teller (BET) analysis (Quantachrome, Boynton, FL, USA), and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) (SEM: Quanta FEG 250, FEI Company (Thermo Fisher Scientific), Hillsboro, OR, USA), were used to investigate the potential of camel dung catalysts to produce biodiesel.

3.2. Transesterification Reaction

The transesterification procedure, which converts triglycerides from date seed oil into biodiesel and glycerol, was carried out in a 50 mL round-bottomed flask with the synthesized catalysts (Figure 8a). A thermocouple was used to both monitor and regulate the reaction temperature. The admixture was continuously mixed using a magnetic stirrer that was placed in the container. The experiment used specified reaction circumstances, in which a certain quantity of the chosen oil was introduced into the reactor at a stirring velocity of 1000 rpm after it had been preheated to a temperature of 60 °C. The temperature of the reaction was controlled by immersing the flask in an oil bath. After measuring out and dispersing the catalyst in ethanol, the required quantity of hot date seed oil was added to the flask. Changes were made to the catalyst loading, ethanol/oil molar ratio, reaction temperature, and reaction duration to maximize biodiesel output by transesterification. Following the completion of the procedure, the solution was subjected to a cooling process and then transferred into a separate funnel (Figure 8b). Distinct layers were generated by the catalyst, glycerol, and the ethyl ester. The product was allowed to stand overnight to achieve good separation. Following an overnight incubation, distinct stages became readily distinguishable. Subsequently, the biodiesel layer was combined with a volume of 15 mL of distilled water and agitated on a heated surface for a duration of 15 min. The resulting mixture was then transferred to a separating funnel and allowed to stand undisturbed for a period of 24 h, resulting in the formation of two distinct and transparent layers. The underlying stratum was eliminated, and the stratum consisting of biodiesel was combined with 0.05 g of sodium sulfate and agitated for a duration of 10 min. Subsequently, the mixture was separated to determine the mass of the biodiesel layer.

The yield of biodiesel was calculated using the following equation:

$$\mathrm{Yield} \%={\displaystyle \frac{Weight of biodiesel produced}{Weight of sample oil used}}\times 100$$

(1)

The final output of biodiesel was subjected to examination and used. The specimens underwent characterization using gas chromatography–mass spectrometry (GC-MS) utilizing a PerkinElmer Clarus 600 instrument (National Research Center, Giza, Egypt), which was outfitted with a DB-wax column. Furthermore, the experimental parameters were enhanced to provide a suitable framework to produce biodiesel from economically viable raw materials in an environmentally beneficial way. The catalysts that were recovered were then utilized in the succeeding reaction.

For the phytochemical screening test, the screening of camel dung was conducted following the standard procedure [20].

3.3. Basicity Calculation

The basicity of a catalyst is defined as the number of basic sites present on a solid substance relative to its total mass. This quantity is often reported in millimoles (mmol) of basic sites per gram of solid. Titration was used to evaluate the starting materials and the resulting catalyst for their basicity. Approximately 0.2 g of the material was introduced into a 50 mL solution of hydrochloric acid (HCl) with a normality of 0.2 N. The mixture was thereafter agitated until complete dissolution occurred. Subsequently, the solution underwent treatment with a total of three drops of phenolphthalein indicator. Ultimately, the solution underwent titration with a 0.2 N potassium hydroxide (KOH) solution until a discernible change in color occurred. The degree of basicity was thereafter ascertained by using Equation (2) as follows:

$${\mathrm{B}}_{\mathrm{c}}={\displaystyle \frac{0.2\times ({\mathrm{V}}_{\mathrm{H}\mathrm{C}\mathrm{l}}-{\mathrm{V}}_{\mathrm{K}\mathrm{O}\mathrm{H}})}{{\mathrm{M}}_{\mathrm{s}}}}$$

(2)

The variable V_HCl represents the quantity of hydrochloric acid (0.2 N) used throughout the titration process, whereas V_KOH denotes the quantity of potassium hydroxide (0.2 N) necessary to neutralize the hydrochloric acid. Additionally, M_S signifies the mass of the sample being analyzed, measured in grams. The term “B_C” refers to the basicity of a substance, which is measured in millimoles of hydrochloric acid per gram of sample.

The calcined samples were subjected to X-ray diffraction analysis (XRD) (Bruker D8 Advance, Bruker, Rheinstetten, Karlsruhe, Germany). using a Bruker D8 Advance diffractometer manufactured in Rheinstetten, Karlsruhe, Germany. The diffractometer used in this study is equipped with a copper anode, which generates Ni-filtered CuKα radiation (k = 1.5406). The radiation is produced by a generator operating at 40 kV and 40 mA. The diffraction measurements were conducted between the 2θ range of 20 to 80. The instrument’s functionality is maintained using interfaces such as DIFFRAC. SUITE and DIFFRAC EVA, which provide an automated process of searching and matching crystalline phases for identification purposes. In the BET analysis, catalyst samples weighing 1 g were subjected to a degassing process lasting 50 min at a temperature of 120 °C inside a sample tube. This procedure was carried out to remove any moisture and other surface impurities present on the catalyst samples. The tube was allowed to reach the surrounding temperature prior to its connection with a gas intake, namely liquid nitrogen at a temperature of −196 °C. This gas intake was positioned parallel to an empty reference tube. Both tubes were submerged in liquid nitrogen inside a Dewar flask.

4. Conclusions

This research demonstrated the potential of camel dung as a novel catalyst for biodiesel synthesis (86 wt% biodiesel yield). This approach showcased an environmentally friendly and sustainable method for biodiesel production, utilizing a widely available biomass resource. The use of inedible date seed oil in this study as agricultural waste presents a promising opportunity to produce biodiesel. This is particularly significant due to the prevailing environmental concerns and the diminishing reserves of petroleum-based fuels, which pose substantial challenges to the advancement and sustenance of human standards of life. The reaction parameters that yielded the highest productivity were determined to be as follows: a temperature of 75 °C, a time of 3 h, a molar ratio of ethanol to date seed oil of 8:1, and a catalyst loading of 4 wt%. These specific conditions resulted in a maximum biodiesel production of 86 wt%. Date seed oil is an excellent biomass feedstock for renewable energy sources, which will contribute to the elimination of global pollution. By means of GC–MS analysis, the chemical composition and presence of FAMEs in the biodiesel sample were verified. Extensive research has been conducted to examine and evaluate the fuel properties of synthetic fatty acid methyl esters (FAMEs) in relation to the established requirements outlined by the ASTM. Future research is warranted to go into more detail in the areas of cost estimation, engine performance, and the mitigation of smoke emissions in the manufacturing of biofuels.