Modeling and Optimization of Reactive Extraction of Gallic Acid Using RSM

Reactive extraction was experimentally investigated for recovery of gallic acid (GA) from the aqueous solution using tri-n-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 (CGA0) in aqueous phase and concentration of TOA (CTOA) 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 (R2 = 99.0%). The optimal extraction conditions of GA were determined as: CGA0 = 2.01 g/L, CTOA = 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%.