No abstract

No abstract

No abstract

This study aims at developing a mathematical model to predict the yield of isoflavone from soybean meal in a supercritical extraction process using carbon dioxide and aqueous methanol as a co‐solvent and to optimize the process using a genetic algorithm. In the model, a partial differential equation based conservation of mass was solved to predict the yield of isoflavone extraction. The model parameters such as densities of carbon dioxide and co‐solvent methanol, the mixture viscosity, the binary diffusion coefficient of isoflavone in the supercritical solvents, the film mass transfer coefficient, effective diffusivity, and axial dispersion coefficient were estimated using available correlations, and the solubility was estimated using the Mohsen‐Nia‐Moddaress‐Mansoori equation of state. The model was successfully validated with experimental data. In the optimization, the operating conditions of the isoflavone extraction process were identified as decision variables and a profit function was maximized. The optimum was found under the condition in which the carbon dioxide flow rate was 5.88 kg/h and the particle diameter was 0.68 mm, when the temperature was 323.15 K, the pressure was 59.45 MPa, and the extraction time was 283 min. The maximum profit found under these optimum conditions was 46.18 $ per batch.

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.