Derived Biobased Catalyst from the three Agro Wastes Peel Powders for the Synthesis of Biodiesel from Luffa Cylindrical, Datura Stramonium, and Lagenaria Siceraria Oil Blend: Process Parameter Optimization

RO. Derived Biobased Catalyst from the three Agro Wastes Peel Powders for the Synthesis of Biodiesel from Luffa Cylindrical, Datura Stramonium, and Lagenaria Siceraria Oil Blend: Process Parameter Optimization. In a bid to replace fossil fuel and developed an ecofriendly based catalyst for the synthesis of biodiesel, this study developed a novel heterogeneous based catalyst from the mixture of Cucurbita pepo, Musa acuminate and Citrullus lanatus peels powders. The developed mixed catalyst was calcined at a temperature of 650oC for 3 h and applied for the synthesis of biodiesel from Luffa cylindrical, Datura stramonium, and Lagenaria siceraria oilseeds. The strength of the basicity of the calcined mixed powder (CMP) catalyst was tested by the catalyst reusability test. Results showed the synthesized catalysts produced high CaO of 62.83%, 65.50%, 58.67%, and 75.65% for calcined Cucurbita pepo, Musa acuminate, Citrullus lanatus peels and the mixed catalyst powders. The blend ratio of 29:50:21 obtained, produced low viscous and high volatile oil used for successful transesterification. Maximum experimental biodiesel yield of 97.20 (%wt.) was obtained, but the statistical analysis predicted a biodiesel yield of 96.63 (% wt.) at the reaction time of 80 min, the CMP amount of 3.53 (g), the reaction temperature of 90oC, and the CH 3 OH/OMR of 1:9 (ml/ml), at the desirability of 95.10%. This value was validated in triplicate, an average mean value of 96.50 (% wt.) was obtained. Analysis of variance (ANOVA) test confirmed the variables were highly significant with p-value<0.0001. Catalyst reusability test showed a significant decrease in the 5 and the 6 th cycle; hence, the test was stopped at the end of the 4 cycle. The produced biodiesel properties conform to the recommended standard. The study concluded that the derived heterogeneous catalyst successfully transformed the blended oil to biodiesel, and the developed catalyst was sustainable.

In a bid to replace fossil fuel and developed an ecofriendly based catalyst for the synthesis of biodiesel, this study developed a novel heterogeneous based catalyst from the mixture of Cucurbita pepo, Musa acuminate and Citrullus lanatus peels powders. The developed mixed catalyst was calcined at a temperature of 650oC for 3 h and applied for the synthesis of biodiesel from Luffa cylindrical, Datura stramonium, and Lagenaria siceraria oilseeds. The strength of the basicity of the calcined mixed powder (CMP) catalyst was tested by the catalyst reusability test. Results showed the synthesized catalysts produced high CaO of 62.83%, 65.50%, 58.67%, and 75.65% for calcined Cucurbita pepo, Musa acuminate, Citrullus lanatus peels and the mixed catalyst powders. The blend ratio of 29:50:21 obtained, produced low viscous and high volatile oil used for successful transesterification. Maximum experimental biodiesel yield of 97.20 (%wt.) was obtained, but the statistical analysis predicted a biodiesel yield of 96.63 (% wt.) at the reaction time of 80 min, the CMP amount of 3.53 (g), the reaction temperature of 90oC, and the CH 3 OH/OMR of 1:9 (ml/ml), at the desirability of 95.10%. This value was validated in triplicate, an average mean value of 96.50 (% wt.) was obtained. Analysis of variance (ANOVA) test confirmed the variables were highly significant with p-value<0.0001. Catalyst reusability test showed a significant decrease in the 5 th and the 6 th cycle; hence, the test was stopped at the end of the 4 th cycle. The produced biodiesel properties conform to the recommended standard. The study concluded that the derived heterogeneous catalyst successfully transformed the blended oil to biodiesel, and the developed catalyst was sustainable. DOI: 10.26717/BJSTR.2021. 40.006483 Italy, Japan, Malaysia, Mali, Mexico, Iran, Ireland, Norway, Germany, etc.) around the globe have shifted attention to biodiesel due to its excellent environmental attributes, sustainability attributes, biodegradability, non-toxic, readily available, and reduction or elimination of over-dependence on fossil fuel [3][4][5][6]. Meanwhile, biodiesel potential feedstocks come from first generation biodiesel feedstocks, which associated with the use of edible vegetable oil (beniseed oil, soyabean oil, corn oil, canola oil, palm oil, sunflower oil, coconut oil, olive oil, linseed oil, peanut oil, corn oil, papaya oil, etc.), the second generation biodiesel feedstocks, which make use of non-edible vegetable oil and animal fat (Jatropha curcus oil, pongamia pinnata oil, waste cooking oil, yellow oleander oil, cotton oil, grease, tallow, rapeseed, castor oil, karanje oil, neem oil, fish fat, pig fat, rubber seed oil, etc.), and the third generation biodiesel feedstocks, which involve the use of microalgae, algae, fungi, bacteria, latexes [5,[7][8][9][10][11][12][13][14][15]. Nevertheless, exploiting firstgeneration biodiesel feedstock leads to a major problem especially in the present world of food shortage [16]. On the other hand, the use of third generation biodiesel feedstock requires a large amount of water for algae productivity, significant fertilizer for algae growth, high production cost using current technology, the long time needed for conversion to biofuel, contenders with regional suitability issues, lack of energy-efficient product, variations in the biofuel quality, and monoculture issue. Therefore, non-edible feedstocks in second-generation biodiesel feedstock are the only secure and viable future for all through biofuel production.
Meanwhile, it has been reported that the use of mix/blend oil tends to improve the yield and the quality of biodiesel; hence, researchers have reported the use of different blend ratios of oil for biodiesel synthesis. Khalil, et al. [17] reportedly the used oil blend ratio of 40:60 for rubber seed oil and palm oil, with NaOH as a base catalyst. The study reported by Qiu, et al. [18] adopted a ratio of 50:50 for the mixture of soybean and rapeseed oil with NaOH as a base catalyst. Milano, et al. [19], combined cooking with Calophyllum inophyllum oil in the ratio of 75:25, with KOH f as a base catalyst, while Hadiyanto, et al. [20] combined waste cooking with castor oil in the ration of 1:0, 1:2, and 2:1, respectively. Falowo, et al. [21], reported a blend of Neem and rubber oil in a 60:40 ratio with a base catalyst developed from elephant-ear tree pod husk.
The work recently reported by Falowo, et al. [22], adopted the ternary blend ratio for Honne-Rubber-Neem oil, with mixed catalyst from three agro wastes. Observation from the reports showed that only Falowo, et al. [21,22] used heterogeneous catalysts for the synthesis of biodiesel production via oil blend. This was due to the heterogeneous catalytic nature such as reusability, recyclability, less water usage, non-toxic, low cost, eco-friendly, and high purity of by-product over the use of homogeneous catalysts (NaOH/KOH) [16,23,24]. To the author's awareness so far, no single report on the use of the API gravity ratio has been reportedly used for oil blend for biodiesel synthesis. Also, no report has ever derived a based catalyst from the mixture of three green wastes of Cucurbita pepo, Musa acuminate, and Citrullus lanatus unripe peels for catalytic application. Literature survey showed that the unripe Cucurbita pepo peels contain 27.85% calcium [25] while unripe Musa acuminate peels contained 57% calcium mineral [26], the calcium content found in Citrullus lanatus unripe peels was reported to be 43% [27]. Proper processing of the peels through drying, sieving, and calcination at a higher temperature above 550 o C has been established as a way of improving the content of the calcium in the peels [28][29][30].
Hence, this work focusses on the synthesis of a mesoporous

Materials
Matured, Luffa cylindrical, Datura stramonium, Lagenaria siceraria seeds were collected from the nearby location around the rural house, Omu-Aran, Kwara State with proper permission obtained from the landowner in Nigeria. The seeds were separated from the husks by sundried for two weeks (14 days), and then oven-dried to a constant weight. The husk Datura stramonium has started splitting even before oven dried. The separated dried seeds were further obtained purely by winnowing and then milled into powders of 0.30 mm particle sizes, kept in separate cleaned containers for further processing (oil extraction). Cucurbita pepo, Musa acuminate, and Citrullus lanatus peels were obtained from the fruits. The peels were washed with distilled water twice, sundried for five days (5 days), and then oven-dried in a DHG-9101-02 oven at 80 o C for 2 h to achieved constant weight. The dried peels were milled into powders, separated into small particle sizes using a mesh strainer (mesh size: 125 mm-20 μm) to aid calcination. The for Datura stramonium and LS2019 for Lagenaria siceraria. All chemicals used were of analytical grades and need no further purification.

Methods
Oil Extraction: Oil extractions from the powders were carried out using solvent extraction in 1 L soxhlet extractor apparatus.
Since the heating mantle was designed to handle three-Soxhlet extractors at once, mass extraction was carried out simultaneously.
The oils were extracted from Luffa cylindrical, Datura stramonium, Lagenaria siceraria powders using n-hexane as the solvent. The Oil Blend: The blend is the acts of mixing two or more substances, either miscible or non-miscible. For oils proper mix, it is worthwhile to know that the action of oil always increased by mixing several oils, nevertheless, the order in which the oil must be mixed must be factor properly. Lighter oil with smaller molecules will produce less viscous oils with high volatility, but heavier oil and larger molecules produce high viscous oils with low volatility.
Hence, to obtain a low viscous, low density, and high volatile oil, there is a need for oil mix in an accurate blend ratio to increase the synergistic effect within the blended oil. One must know the nature (heavy or light) of the oil before mixing. The extracted oil is defined with API gravity, API gravity greater than 10 indicated lighter oil and the oil floats on water, the value of API gravity lesser than 10 indicated heavier oil, and the oil sinks on water. The API gravity of oil is calculated using Eq. (1) [31].

Oil Blend via API Gravity Estimate:
The API gravity of the oils was estimated based on the specific gravity of the oil. The total API gravity of the oils was obtained from the API gravity of the oils obtained, the mix ratio of oil was computed using the mathematically derived Eq. (2), and the oil was properly mixed by heating at 50 oC on a magnetic shaker for 30 min.

Synthesis of Biodiesel
The mixed oil (29:50:21) free fatty acid (FFA = 0.82<1.5) was within the moderate value for transesterification of oil to biodiesel [33]. Therefore, transesterification of mixed oil (MO) to biodiesel through methanolysis of the mixed powder (MP) was carried out using the procedure earlier reported by Adepoju, et al. [29] with few modifications. A three-necked-reactor was used to carry out biodiesel production, four factors with five-level were considered h) under agitation. The mixture was filtered, washed with distilled water three times before the separation of biodiesel through gravity settling was carried out. The washed biodiesel was then dried over anhydrous Na 2 SO 4 and then separated by filtration to obtain pure biodiesel. These processes were repeated based on experimental runs generated by response surface methodology experimental design.

Experimental Design for Biodiesel Synthesis and Its
Where FAME is the response (biodiesel) in percentage, P_0 is the intercept, P_i is the linear coefficient, P_ii is the interaction coefficient, P_ij is the quadratic coefficient terms, X_i 〖 and X〗_j are the four factors and ϵ is the residual error.   which appears more porous, brittle and easy to ground.  b. FTIR analysis of CMP at 650 oC for 3h. Figure 1b shows the FTIR spectra of CMP, distinct peaks were noticed at 711.    chance that a "Model F-value" this large could occur due to noise.

Brunauer-Emmett-Teller (BET):
Meanwhile, values of "Prob > F" less than 0.05 show variable terms are significant. In this case, X 1 , X 2 , X 3 , X 4 , X 12 , X 22 , X 32 , X 42 , X 1 X 2 , X 1 X 3 , X 1 X 4 , X 2 X 3 , X 2 X 4 , and X 3 X 4 were remarkable significant variable terms. The coefficient of determination is the correlation coefficient, also known as R-square,which allows it to display the degree of linear correlation between two variables. The value obtained in this study is high (99.94%), indicate a high degree of correlation between the interacting variables. The "Pred. R-Squared" of 99.65% is in reasonable agreement with the "Adj R-Squared" of 99.88%. The "Adeq Precision", which measures the signal to noise ratio. Usually, a ratio greater than 4 is desirable, the ratio of 188.58 obtained in the study specifies an adequate signal.The polynomial model quadratic equation that shows the relationship between the biodiesel yield and the four-variable factors is presented in Eq. (4).   Graphical Plots: Furthermore, the relationship between the response variable (biodiesel) and the interactive variables (X 1 X 2 , X 1 X 3 , X 1 X 4 , X 2 X 3 , X 2 X 4 , and X 3 X 4 ) can be represented in contour and

Catalyst Reusability Test
For catalyst purification and reusability analysis of the reaction

Properties of the Mixed Oil and Biodiesel
Method of AOAC were adopted to examine the properties of the blended oil and the product, the obtained results of the biodiesel were compared with the ASTM D6751 and EN 14214 biodiesel recommended standard (Table 6). It was observed that the decreased in the moisture content, density, viscosity, acid value, the iodine value, saponification, and the peroxide value of the blended oil to biodiesel was due to process transesterification. This confirmed that the synthesized product is consistent with biodiesel and the translation of blended oil complete transesterification reaction to biodiesel was achieved with insignificant resistance to flow and lessen internal drag in the engine. Further observation showed that the cetane number, the higher heating value (HHV), the API gravity, and the diesel index increased as blended oil was converted to biodiesel, this could be attributed to energy formation from viscous oil to low viscous oil. The high biodiesel yield obtained in this study could be attributed to due to decrease base consumption for neutralization. Based on cetane number, the higher the peroxide value, the better the cetane number and the decrease in ignition time [31,40]. The value of 4.34 meq O 2 /kg oil, can be attributed to the cetane number of 57.52 obtained. The higher heating value (HHV) of biodiesel is greater than that of blended oil which signify high heat of vaporization of water in the combustion of biodiesel.
The American petroleum institute (API) gravity usually used to determine the weight of oil/petroleum in comparison with water, the value of 33.03 and 49.91 obtained for blended oil and biodiesel exhibited light oils. Diesel index which denotes the efficiency of the biodiesel as well as the ignition properties, the value obtained in this study were well within the required recommendation standard for biodiesel that can be used in I.C engine [41][42][43][44].

Conclusion
The study concluded that the ratio of blended oil produced low viscous oil, and the derived catalyst from the mixture of Analysis of variance test confirmed the significant of variables with p-value<0.0001. Catalyst reusability test was immobile at the 4th cycle due to loss of basicity that occurred due to leaching as a result of several recyclability during the reaction. Hence, the produced biodiesel conformed to biodiesel recommended standard, and the CaO catalyst could serve as promising economical feedstock for industrial application.