Adsorption of Nickel(II) Ions from Synthetic Wastewater Using Activated Carbon Prepared from Mespilus germanica Leaf

Today one of the major environmental issues is the contamination of surface waters by toxic heavy metals. Such pollutants cannot be decomposed in environment and jeopardize human health. Therefore, the removal of these ions from water and wastewater has been considered as a worldwide concern. In this work, the activated carbon which was produced from Mespilus germanica leaf was used for the removal of Ni2+ ions from aqueous solution, and the effect of operating parameters, namely solution pH (3-10), the dosage of adsorbent (0.1-0.7 g/L), contact time (10-80 min), process temperature (298-348 K), and nickel ion initial concentration (10-70 ppm) were investigated on its adsorption percentage. Additionally, the prepared adsorbent was characterized by BET, SEM, XRD, FTIR, and EDAX techniques. Based on the results of BET analysis, the surface area of the adsorbent was 10.39 m(2)/g. The optimal nickel ions adsorption efficiency was 97.56% which was achieved in the following optimal operating conditions: pH = 7, adsorbent dosage = 0.4 g/L, contact time = 50 min, 298 K, and nickel ion initial concentration = 60 ppm. In addition, the equilibrium and kinetic investigations showed that Langmuir isotherm and the pseudo second-order kinetic models described the equilibrium behavior and kinetics of the current adsorption process well. Langmuir isotherm data showed that the maximum adsorption capacity was equal to 13.08 mg/g. Additionally, the thermodynamic study of the process indicated that Ni2+ ions adsorption by the produced activated carbon was exothermic.