Adsorption of copper and zinc ions on illite: Determination of the optimal conditions by the statistical design of experiments

In this study, a full factorial experimental design was utilized to assess the effect of three factors on the adsorption of copper (II) and zinc (II) ions in an aqueous leachate of an industrial waste with illite as adsorbent. The chosen experimental factors at two levels were (A) pH at 2 and 7, (B) adsorbent content at 0.2 and 1.6 g L− 1, and (C) contact time at 10 and 120 minB (adsorbent content), A (pH), and AB terms, with their high levels, positively influenced the adsorption process. Of the adsorption kinetics models, the second order model best described the data. Illite was a reasonably effective adsorbent for Cu2+ and Zn2+ from aqueous leachates of industrial waste.

Research highlights
► Adsorption studies need to be understood for optimizing the conditions of the process.
► One-factor-at-a-time method is no feasible and inept of getting true optimum condition.
► RSM can reduce time, cost and resources.
► A 23 factorial design is used to determine the optimal conditions in a batch mode.
► Illite is reasonably effective adsorbent for the removal of Cu2+ and Zn2+.