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><sub>GA0</sub>) in aqueous phase and concentration of TOA (<i>C</i><sub>TOA</sub>) 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><sup>2</sup> = 99.0%). The optimal extraction conditions of GA were determined as: <i>C</i><sub>GA0</sub> = 2.01 g/L, <i>C</i><sub>TOA</sub> = 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>