Response surface methodology optimization of Congo Red dye adsorption onto MnFe-LDH adsorbent

This study was carried out to optimize the adsorption process toward Congo Red (CR) dye over Mn-Fe LDH material in aqueous media. The effects of three variables including initial concentration, pH and reaction time were investigated with respect to maximal CR removal efficiency by utilizing response surface methodology (RSM). Through the variance of ANOVA, the second-order polynomial model was established in accordance with experimental data with high R-2 values (R-2=0.997), large F-value and small p-value, indicating that the proposed model is statistically significant. The estimated optimal conditions were validated by confirmation experiments. It was revealed that CR adsorption efficiency reached 53.21% at following optimal conditions: C-i = 48.09 mg/L; pH = 5.62; reaction time = 107 min. These results show that MnFe LDH is used as an effective adsorbent for the removal of organic pigments in aqueous solution.