Kinetics and thermodynamic studies on oil extraction from Ghanaian cashew kernel using hexane

Abstract

This study underlines all the techniques adopted to extract and define the oil that was extracted from cashew kernels and also to figure out if it fits the bill for applications in industrial operations. Using the solvent extraction method, the oil was obtained at different extraction times and temperatures. At the maximum temperature 333 K, the highest yield of the oil (34.7 %) was obtained at the highest extraction time 130 min adhering to first order kinetics. The mass transfer (km) and the regression coefficient (R2) were 0.0115 and 0.9853 respectively. The activation energy (Ea.), the entropy changes (ΔS), the equilibrium constant (K) and the enthalpy change (ΔH) were 59.958 KJmol-1, 228.4 KJmolK−1, 7.54 and 70.29 KJmol-1 respectively. The activation enthalpy (ΔH*), entropy (ΔS*) and Gibbs free energy (ΔG*) were 57.2880 KJmol-1, −0.1617 KJ (molK)−1 and 114.834 KJ mol−1, respectively, favoring an endothermic, irreversible, and spontaneous extraction. The negative Gibbs free energy range of −2.3342 KJ(molK)−1 to −5.7602 KJ(molK)−1 indicated the feasibility of oil extraction from cashew kernels. Also, some major fatty acids compositions that were identified in the oil after characterization were oleic acid (71 %) and linoleic acid (32 %). The oil's bond and potential functional groups were identified using the Fourier Transform Infrared analysis (FTIR) which indicated the presence of O–H, C–H, C–N, CO, C–C and = C–H.

Keywords

• Cashew kernel
• Cashew kernel oil
• Extraction
• Kinetics
• Thermodynamics