Adsorption of pollutants from aqueous solutions using activated and non-activated oak shells: Parametric and fractional factorial design study. Part I. Removal of copper

Non-activated and chemically activated oak shells were evaluated for their ability to remove Cu²⁺ ions from aqueous solutions. Batch adsorption experiments were conducted to investigate the effect of contact time, sorbent concentration, Cu²⁺ ion concentration and the pH of the solution on the sorption process. The Cu²⁺ ion uptake by oak shells increased with decreasing sorbent concentration or with an increase in Cu²⁺ ion concentration or solution pH. The fractional factorial design technique was applied in order to determine the average Cu²⁺ ion uptake, the contribution of each operating variable to the value of the uptake and the interaction among the operating variables when the sorbent type, sorbent concentration, Cu²⁺ ion concentration. pH, contact time and salt were all varied from one level to another. Application of this technique showed that the sorbent concentration had the largest influence on the value of the Cu²⁺ ion uptake followed by Cu²⁺ ion concentration and sorbent type. Interaction among the different operating variables played an important role in the adsorption process.