Removal of Ni(II) Ions From Aqueous Solutions Using Activated-Carbon Prepared From Olive Stone by ZnCl2 Activation

The aim of this study is to remove Ni (II) ions from aqueous solutions by adsorption. Activated-carbon prepared from olive stone (ACOS) was used as adsorbent. Different particle size and concentration of ZnCl2 were studied to optimize adsorbent surface area. Initial concentration, temperature, time, and pH were selected as parameters. According to the experiments results, the equilibrium time, optimum pH, and adsorbent dosage were found 60 min, pH > 6, and 1.0 g/50 mL, respectively. In addition, raw olive stone was used as adsorbents at the same parameters. Nickel removal percentage for ACOS and Raw Olive stone were obtained 95.00% and 38.00% in turn. The kinetic data supports pseudo-second-order model strongly. In addition, the thermodynamic parameters Delta G degrees, Delta H degrees, and Delta S degrees were found -6.185 kJ mol(-1), -10.997 kJ mol(-1), and -15.889 J/mol K, respectively. Scanning electron microscopy (SEM-EDX) technique was employed to observe the surface physical morphology and structural analysis. The resulting activated carbons with 20% ZnCl2 solution was the best sample of the produced activated-carbons from olive stone with the specific surface area of 790.25 m(2)g(-1). The results indicated that ACOS could be employed as an alternative adsorbent for removing Ni (II). (C) 2009 American Institute of Chemical Engineers Environ Prog, 28: 547-557, 2009