Ultrasonication Assisted Catalytic Transesterification of Ceiba Pentandra (Kapok) Oil Derived Biodiesel Using Immobilized Iron Nanoparticles

Abstract

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 ΔE of 30.79 kJ mol−1. The ΔH was found to be 28.06 kJ mol−1 with a corresponding ΔS of −237.12 J mol−1 K−1 for Fatty Acid Methyl Ester formation. The ΔG 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 ΔH and ΔG is an indication of endothermic and non-spontaneous reaction. A negative ΔS 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.

Emerging trends in the appliance of ultrasonic technology for valorization of agricultural residue into versatile products

“…The ultrasound treatment applies to the preparation or assisting of valuable materials production from agro-residues such as cellulose nanocrystals (CNC), cellulose nanofibers (CNF), reducing sugars, lignin nanoparticles, chitosan, biochar, biodiesel, etc. [76] , [77] , [78] , [79] , [80] , [81] . Below are the literature studies on producing a value-added product from agro-residue.…”

Recent Developments in Catalysts for Biodiesel Production Applications

“…Various nanocatalysts are used for biodiesel production from different sources[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43].FFA and moisture contents, promoting simple recovery, reusability, low cost, and green process. They can also be modified to increase activity, selectivity, and catalyst lifetime[53,54].…”