Yield enhancement through synergism by ultrasonication assistance in the transesterification of fig seed oil using waste fig leaves catalyst

Abstract

Transesterification of fig-seed oil (fso) using a waste biomass-derived fig leaf biocatalyst (flbc) through a synergistic effect of optimised conventional and ultrasonication parameters is reported. Conventional parameters, such as reaction temperature (rT), reaction time (rt), and catalyst dosage (Cd) were optimised through systematic experimental trials. Ultrasonication parameters such as probe diameter (Pd), irradiation distance (Id), ultrasound pulse (Up), and ultrasound amplitude (Ua) were optimised using a 4-factor-3-level, Box-Behnken experimental design coupled with the fuzzy logic method. The optimum transesterification conditions of rT = 40 ˚C, rt = 20 min, Cd = 1.0 wt%, and Pd = 30 mm, Id = 75 mm, Up = 38 %, Ua = 60 % yield 91.7 % fig seed oil methyl ester (FSME) i.e., fig seed oil biodiesel. The transesterification follows pseudo-first-order kinetics with the activation energy of 20.53 kJ/mol which minimizes the energy requirements to ∼ 15 times and enhances the FSME yield to 7.5 % than the yield reported in the literature. A comparison with the literature data suggests that the proposed reaction condition would help to reduce the production cost in terms of energy requirements, i.e., power consumption of 53.2 Wh is sufficient to yield 91.7 % of FSME by the synergism of optimal conventional and ultrasonicated transesterification conditions, instead of 829.6 Wh for an 84.2 % as reported in the literature.