Usefulness of Response Surface Method by Application of Box-Behnken Design for Optimizing Cd and Cu Sorption from Aqueous Solutions by Chitosan

Existence of heavy metals in water resources and wastewater can cause the environmental problems. Use of low-cost substances as adsorbents has been developed over recent years. The purpose of this study was to investigate the effect of chitosan on sorption of Cd and Cu heavy metals from aqueous solutions using response surface method and Box–Behnken methods.  The batch experiment was conducted to evaluate the effects of independent variables such as pH, metal concentration, and ionic strength on the metal sorption using response surface and Box–Behnken methods. One-way analysis of variance (ANOVA) was applied on data. High values of R2 (0.99) and adjusted R2 (0.99) showed that the removal of Cu and Cd can be described by the response surface method. One-way ANOVA showed (p < 0.001) that quadratic was the best model for determining the interaction variables. The optimal conditions determined for Cu and Cd initial concentrations, pH and ionic strength values were 200 and 168.8 mg L-1, 5.47 and 5.26 and 0.03 M, respectively. The predicted adsorption at these settings for Cu and Cd were 83.68 and 45.07 mg g-1, respectively. Response Surface Method could be useful for optimization the adsorption of Cu and Cd from aqueous solutions by chitosan