2.1. Extraction of oil
The extraction process was conducted using soxhlet and batch
extractors. The soxhlet and batch extractors’ setup includes
100 ml laboratory soxhlet and a 250 ml jacketed glass reactor. Mixing and heating of the solvent was provided by a hot digital magnetic
stirrer. Cold water circulation was controlled by water bath,
RC (LAUDA). Solid coconut waste was weighted and experiment
was conducted using batch and soxhlet extractor. Solid coconut
waste was grinded for 10 min using a coffee grinder and separated
with sieve plates.
Temperature for batch reactor was varied between 55 and
65 C, which is below the boiling point of the hexane and for the
soxhlet extractor; the temperature range was between 70 and
80 C, above the boiling point of the solvent. Hexane and petroleum
ether were used as solvents for both of the setup to separate
the oil from the waste. The coconut waste was separated by sieving
into three types of particle size, 0.5 mm and below and 0.7 mm and
below and 1.2 mm and below to determine the optimum size and
to obtain the highest oil yield. Solvent to solid mass of coconut
waste were varied from 6:1 to 12:1. The extraction process was
conducted for 15, 30, 45 min and 1, 2, 3, 4 and 5 h. After the equilibrium
was reached, the solvent was recovered using a distillation
system. For batch extractor, the mixture was filtered using Buchi
filter attached to vacuum pump to separate the coconut waste
and solution which contains oil. Solvent was used to wash the meal
for few times to obtain all the oil. The oil yield (oil content) of the
coconut waste was calculated as below: