Investigation of 2,4-dichlorophenoxyacetic acid adsorption onto MIEX resin: Optimization using response surface methodology

This study investigated the optimization of process parameters in terms of 2,4-dichlorophenoxyacetic acid (2,4-D) removal from raw water by using magnetic ion exchange (MIEX) resin. Response surface methodology was applied to find out the major parameters influencing 2,4-D removal efficiency. Moreover, the optimal values of these parameters and the interactions between them were investigated (pH, MIEX dose and reaction time). The experimental data of variables showed a high correlation with the second-order polynomial model, with a coefficient of determination value (R2) of 0.9945 in terms of 2,4-D. Multiple response optimization was also employed to the experimental data to discover the optimal conditions for a set of response, simultaneously, by using a desirability function. The optimum pH, adsorbent dose and reaction time were found to be 6.06, 1.0 mL/L and 52.33 min, respectively. The highest removal of 2,4-D (97.02%) was reached under these conditions. After the process optimization, the MIEX treatment was proven to be a good option for the removal of 2,4-D.