Valorization of Restaurant Waste Oil Over Cow-bone Doped Siliceous Termite Hills Catalysts Towards Biodiesel Production

26 Treated termite hill is a potent heterogeneous catalyst in the synthesis of biodiesel from 27 restaurant waste oil (RWO). Two catalysts (raw cow-bone supported on silica; R-SC 1.5 and 28 calcined cow bone supported on silica; K-SC 1.5 ) were developed and used in biodiesel 29 production. The maximum conversion of RWO was 95.12 % using K-SC 1.5 at reaction time 2.5 30 h, methanol to oil ratio 9:1, temperature 65°C and catalyst loading of 2 %w/w. The prepared 31 catalysts were characterized using SEM, EDAX, FTIR, XRD and BET analysis. The kinetics of 32 the RWO with R-SC 1.5 and K-SC 1.5 was further studied. The E a and A were found to be 41.4 kJ 33 mol -1 , 53.41 kJ mol -1 and 2.24 ×10 4 min -1 , 2.29×10 6 min -1 respectively. The transesterification 34 reaction adhered to first order law, while physicochemical properties were within ASTM limits. 35 Reusability of K-SC 1.5 was also examined, which revealed effectiveness up to 5 reuses without 36 significant reduction in biodiesel yield. 37 38 39 40


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In the world today, conventional fuels such as natural gas, coal, petroleum etc. are the major 54 sources of energy, however their extensive use has an irreversible impact on the ecosystem  Transesterification is also frequently coupled with esterification, usually as a pre-treatment step 75 for oils that have high amounts of FFAs and are hence unsuitable for alkali-catalyzed conversion 76 due to saponification and hydrolysis (Karmakar and Halder 2019). Here, polar alcohols could 77 convert the FFAs into esters, usually aided by mineral acids that act as a catalyst, and non-polar 78 alcohols are unable to participate in this conversion (Karmakar et al. 2020c). The benefits of 79 biodiesel include biodegradability, high lubricity, low toxicity, high calorific value and high 80 combustion efficacy due to increased oxygen (10 to 11%) and virtually no sulphur. Nevertheless, 81 biodiesel commercialization is hindered by its high total cost of synthesis (Babatunde et al.     156 To prepare the support, the termite hill was pulverized into powder. The powder was dissolved 157 in distilled water and mixed thoroughly and left standing for 36 h. After decantation of the 158 excess water, the termite hill was air-dried for 2 days, crushed into powder and dried again in an 159 oven at 120 °C for 2 h to remove residual moisture. The powdered termite hill was sieved using  To prepare the catalysts, the pretreated cow-bone (C) 1.5 wt % (relative to the weight of support) 169 was added to 10 g silica. The mixture was dissolved in 50 mL water before being placed in an 170 orbital shaker at 200 rpm and kept at 30 °C overnight. Filtration of the solution yields a solid 171 sample (SC1.5), which was dried at room temperature for 24 h and called raw cow-bone 172 supported on silica (R -SC1.5). The R -SC1.5 was then calcined at 900 °C for 2 h, and then called 173 calcined cow bone supported on silica (K-SC1.5) and then stored in a desiccator.

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The prepared catalysts (R -SC1.5. and K -SC1.5) were analyzed to estimate its physical properties 176 such as surface area and pore volume. The analysis was performed using the multi-point BET Where -Ra = rate of reaction; TGs = triglyceride concentration, k' = equilibrium rate constant, 218 MtOH = methanol concentration. Since, the concentration of methanol did not alter the reaction 219 order, it is appropriate to theorize that the reaction adheres to a pseudo-first order reaction.

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Hence, the Eq.3 has been adapted for the reaction order.    be confirmed from other non-major peaks in the spectrum.

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As depicted in Fig. 4, the FTIR spectrum of K-SC1.5 was also investigated. The wavenumber 294 between 3400 cm -1 and 3650 cm -1 represents symmetric and asymmetric -OH stretching of H-

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The temperature was varied between 50-65°C so as to investigate the kinetics of the reaction. In Fig. 6, the RWO conversion tends to increase as the reaction temperature increases. The 318 maximum yields attained by R-SC1.5 and K-SC1.5 were 68.1% and 95.12% respectively. Hence, it 319 is worthy of note to state that the higher conversion attained by K-SC1.5 was due to the influence 320 of calcination on the catalyst (Farooq et al. 2015).   In order to deduce the kinetic parameters, -ln(1-x) was plotted against t as shown in Fig. 8 and   344 the correlation coefficients were ˃0.9 for both catalysts. As shown in Fig. 9, the Ea and A were

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In this study, we investigated biodiesel synthesis from restaurant waste oil (RWO) with R-SC1. Availability of data and materials 383 All data generated or analyzed during this study are included in this article.