Removal of Cadmium and Zinc Ions by Iron-Impregnated Activated Carbon Prepared from Tunisian Date Stones

To protect the environment and human health from mineral pollutants recently highly rejected, the reuse of waste as adsorbent may be both efficient and economical solution to remove or reduce these environmental hazards. The iron (hydro) oxide impregnation of activated carbon produced from date stones was performed in this study to investigate the removal of Cd and Zn ions from aqueous media in individual and competitive systems. Adsorption tests were performed using both wastewater and synthetic solutions containing Cd or Zn (single system) and both Cd (II) + Zn (II) in the reactional medium (binary system). The pH value for maximum retention was 5.5 for both elements after an optimum contact time about two hours. Langmuir model was considered the best fit for the metal ions removal at 20 °C in both individual and competitive systems in one hand. In another hand, isotherm modulizations demonstrated the efficiency of the impregnated activated carbon in both single and binary systems compared to non-impregnated carbon. Iron-impregnated activated carbon preferentially adsorbed cations in the following order: Cd (II) in single system > Cd (II) in binary system > Zn (II) in single system > Zn (II) in binary system. Results demonstrated that iron-impregnated AC obtained from date stones waste may be used as a promising material to removal heavy metals ions (Cd and Zn) from wastewater.