LINEAR KINETICS MODELLING AND THERMODYNAMICS STUDY OF SUPERCRITICAL CO2-DERIVED OIL EXTRACTS FROM PALM FRUIT MESOCARP

Abstract

Supercritical fluid extraction (SFE) is a green processing technique that employed the use of carbon dioxide (CO 2 ) as an extractant in place of organic or inorganic solvents. In this study, SFE was used to recover oil from the milled palm fruit peels as a sustainable feedstock. The process was carried out at five different temperatures of 40°C-80°C, varied extraction time of 30-150 min, a fixed pressure of 25 MPa, a flow rate of 5 mL min -1 , and a co-solvent ratio of 5.00% vol. The result shows that an optimum extract yield of 3.95% was recovered at the maximum temperature (80°C) after 150 min. The experimentally obtained data were subjected to kinetic analysis using Elovich’s, Hyperbolic and Pseudo second-order models. Models’ suitability to the data fitness was tested using seven error functions, in which Elovich’s was found to be the best-fitted model, succeeded by the Hyperbolic and then Pseudo second-order. Also, the result of statistical analysis using ANOVA, indicates that temperature has more impact on improving the rate of extract recovery than extraction time. Finally, the thermodynamic studies revealed that an irreversible and endothermically forward reaction was observed considering the values of the entropy change (ΔS) = 0.138 J mol -1 K -1 , enthalpy change (ΔH) = 53.50 K J mol -1 , and Gibbs’ free energy, (ΔG) = -6.04 K J mol -1 respectively.