Rapid removal of mercury ion (II) from aqueous solution by chemically activated eggplant hull adsorbent

Eggplant hull (EH) as a waste material was introduced as a new adsorbent through activation process followed by a chemical treatment method using H2O2 and NH3. For the first time, the EH adsorption was used for the adsorptive removal of mercury ion (Hg++) from aqueous solutions and the effects of different parameters, including pH of solution, contact time, temperature, and initial concentration, on the adsorption efficiency were studied. The results revealed that the EH, as an effective adsorbent, has high adsorption activity in higher pH values. The temperature study indicated the endothermic nature of the adsorption processes. Also, the Hg (II) adsorption by EH follows the pseudo first order kinetic model and both Langmuir and Freundlich isotherm models. However, Freundlich adsorption model fitted the experimental data better than Langmuir model. The maximum adsorption capacity of EH was obtained 147.06 mg/g which was higher than most conventional adsorbents. The surface activity of EH was estimated using iodine method as 300 mg/g.