The reusability of prepared catalyst was tested under the optimum
transesterification conditions of 5 wt.% catalyst loading, 15:1
methanol to oil molar ratio, 65 C reaction temperature and reaction
time of 4 h. After each run, the spent catalyst was recovered,
washed with n-hexane to remove the adsorbed materials. This
catalyst was later calcined at 400 C for 2 h to reactivate it for
transesterification of waste cooking oil. The results showed (Fig. 8)
that the catalyst can be reused for consecutive four runs with
excellent activity in transesterification reaction of WCO for biodiesel
production. However, in the fifth and onward runs biodiesel
yield was found to decrease. The decrease in biodiesel yield after
each run may be attributed to the deposition of unreacted oil,
biodiesel or glycerol on the active sites present on the surface of the
catalyst [37]. Chicken bone is therefore a useful rawmaterial for the
preparation of a cheap catalyst for biodiesel production.