Valorization of restaurant waste oil and cow-bone doped siliceous termite hills towards biodiesel production: Kinetics and thermodynamics
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Date
2022
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Journal ISSN
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Publisher
Sustainable Chemistry and Pharmacy: Elsevier B.V.
Abstract
The type of feedstock and catalyst selected are major factors in determining the process effi
ciency, product cost and fuel yield obtained from a biodiesel production process. The use of ter
mite hill as a highly reusable inert support, doped with cow bones in the synthesis of biodiesel
from restaurant waste oil (RWO) could be a cost-effective alternative to other conventional cata
lyst types or processes. Therefore, two catalysts (raw cow-bone supported on silica; R–SC1.5 and
calcined cow bone supported on silica; C-SC1.5) were developed and used in biodiesel production.
The maximum conversion of RWO was 95.12% using C-SC1.5 at reaction time 2.5 h, methanol to
oil ratio 9:1, temperature 65 °C and catalyst loading of 2 %w/w. The prepared catalysts were
characterized using SEM, EDX, FTIR, XRD and BET analysis. The kinetics of the RWO with
R–SC1.5 and C-SC1.5 was further studied. The activation energy (Ea) and frequency factor (A) were
found to be 41.4 kJ/mol, 53.41 kJ/mol and 2.24 × 104 min−1, 2.29 × 106 min−1 respectively.
The transesterification reaction adhered to first order law, while physicochemical properties of
the biodiesel obtained were within the American Standard for Testing and Materials (ASTM) lim
its, since the product has low FFA content, low viscosity, high thermal stability with high energy
content and improved combustion characteristics. Reusability of C-SC1.5 was also examined,
which revealed effectiveness up to 5 reuses without significant reduction in biodiesel yield.