Modeling and Optimization of Reactive Extraction of Gallic Acid Using RSM

<p>Reactive extraction was experimentally investigated for recovery of gallic acid (GA) from the aqueous solution using tri-<i>n</i>-octylamine (TOA) as extractant in hexanol. All experiments were carried out according to statistical design in order to develop a regression model used to optimize the extraction of GA. Two independent variables were selected as: initial concentration of GA (<i>C</i>_GA0) in aqueous phase and concentration of TOA (<i>C</i>_TOA) in organic phase. The statistical analysis showed that both the independent variables had significant effect on response value, followed by the quadratic and interactive effect on response. A five-level central composite rotatable design (CCRD) was employed. Analysis of variance (ANOVA) showed a high coefficient of determination (<i>R</i>² = 99.0%). The optimal extraction conditions of GA were determined as: <i>C</i>_GA0 = 2.01 g/L, <i>C</i>_TOA = 6.8% v/v. At the optimum conditions, the experimental yield of GA was 91.9%, which was in close agreement with the predicted value of 93.2%.</p

Effect of Temperature on Reactive Extraction of Gallic Acid Using Tri‑<i>n</i>‑butyl Phosphate, Tri‑<i>n</i>‑octylamine and Aliquat 336

The present work is focused on the effect of temperature on extraction of gallic acid using Aliquat 336, tri-<i>n</i>-butyl phosphate and tri-<i>n</i>-octylamine in hexanol and octanol. Distribution coefficient, loading ratio, percent extraction, equilibrium complexation constant, water coextraction, enthalpy, and entropy change were evaluated for various acid–extractant–diluent combinations with varying temperature. The extraction of GA was found to be highly exothermic at lower molality of TBP in octanol with evaluated enthalpy change as −28 743 J/mol. The extraction of gallic acid process was favored at low temperature as the process was evaluated as an exothermic in nature. Maximum extraction efficiency of 97.3% was observed at higher molality of Aliquat 336 in hexanol at lower temperature