Response Surface Methodology for Optimizing Adsorption Process Parameters of Amaranth Removal Using Magnetic Layer Double Hydroxide (Fe3O4/ZnFe-LDH)

ABSTRACT Response surface methodology was employed to optimize the adsorption parameters of Amaranth onto magnetic layer double hydroxide (Fe3O4/ZnFe-LDH). Such optimization was undertaken to ensure a high efficiency over the experimental ranges employed, and to evaluate the interactive effects of the initial concentration of Amaranth, pH, adsorbent dosage, temperature and contact time on the adsorption process in order to improve the conditions employed in the batch process. A total of 32 desorption experimental runs were carried out employing the detailed conditions designed by response surface methodology based on the Box–Behnken design. The analysis of variance (ANOVA) indicated that a second-order polynomial regression equation was the most appropriate polynomial for fitting the experimental data. The experimental confirmation tests showed a correlation between the predicted and experimental responses (R2). The optimal point obtained was located in the valid region and the optimum adsorption parameters were predicted as an initial Amaranth concentration of 70.93 mg/L, a pH value of 3.6, adsorbent dosage of 0.01 g, a temperature of 31.82°C and contact time of 16.83 min.