Fig. 1: Effect of temperature on the oil yield of IGK at
different average particle sizes (mm): (a) 0.5, (b) 1.0, (c) 1.5, (d)
2.0, and (e) 2.5 mm
Effect of particle size
Extraction rate increases as the particle size decreases [26,54].
Fig. 2a and b shows the effect of particle size on the extraction of oil
from IGK using hexane as solvent. The particle sizes considered in this
study were 0.5, 1.0, 1.5, 2.0 and 2.5 mm. It could be seen that their
(particles sizes) respective oil yields were 60.08, 42.01, 39.70, 37.18
and 35.4 %, at 35 °C and 150 mins. This shows that highest oil yield
was obtained with the smallest particle size of 0.5 mm, and the least
with the largest particle size of 2.5 mm. These findings were in line
with the works of Sulaiman et al. [26] and Huang et al. [55],
for the extractions of solid coconut waste oil and Baizhu, respectively.
The additional oil extracted from smaller particle size was attributed
to the larger interfacial area of the solid present in them. Also, the
solvent requires minimal distance to penetrate the solid particles in
other to extract oil from it. In other words, contributes to increase in
pore diffusion between the solute (solid) and the solvent. On the other
hand, larger particles have limited contact surface area, which causes
more resistance to solvent penetration and oil diffusion. Hence, smaller
quantity of oil would be transported from the inside of the larger
particles to the surrounding solution [26,53].
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