Ultrasonification Assisted Catalytic Transesterification of Ceiba Pentadra (Kapok) Oil Derived Biodiesel Using Immobilized Iron Nanparticles

The embedded immobilized enzymes (Rhizopus-oryzae) on the magnetic nanoparticles
(Fe3O4-NPs) is a new application for the sustainable production of high-quality biodiesel. In this
study, biodiesel is derived from Kapok oil via ultrasonication (US)-assisted catalytic transesterification
method. A novel attempt is made to prepare magnetic nanoparticles embedded by an immobilized
enzyme to solve the problem of enzyme denaturation. This innovative method resulted in optimum
biodiesel conversion of 89 1.17% under reactant molar ratio (methanol: oil) of 6:1, catalyst loading
10 wt% with a reaction time of 4 h at 60 C. The kinetic and thermal study reveals that conversion of
Kapok oil to biodiesel follows a pseudo first-order reaction kinetic with a lower DE of 30.79 kJ mol􀀀1.
The DH was found to be 28.06 kJ mol􀀀1 with a corresponding DS of 􀀀237.12 J mol􀀀1 K􀀀1 for Fatty
Acid Methyl Ester formation. The DG was calculated to be from 102.28 to 109.40 kJ mol􀀀1 for
temperature from 313 K to 343 K. The positive value of DH and DG is an indication of endothermic
and non-spontaneous reaction. A negative DS indicates the reactant in the transition state possesses a
higher degree of ordered geometry than in its ground state. The immobilized catalysts provided great
advantages towards product separation and efficient biodiesel production. Highlights: 1. Effective
catalytic transesterification assisted by the ultrasonication method was used for bi-odiesel production.
2. Magnetite nanoparticles synthesized by the co-precipitation method were used as heteroge-neous
catalysts. 3. An immobilized enzyme (Rhizopus-oryzae) was embedded in the heterogeneous catalyst,
as it is reusable and cost-effective. 4. The maximum biodiesel yield obtained from Kapok oil was
93 1.04% by catalytic trans-esterification reactions.