Removal of Ni (II) from aqueous solutions by adsorption onto <i style="">Cajanus cajan L </i>Milsp seed shell activated carbons

Abstract

The adsorptive removal of Ni(II) from aqueous solution using <i>Cajanus cajan L </i>Milsp seed shells activated carbon (CCC) and polypyrrole coated <i>Cajanus cajan L </i>Milsp seed shells activated carbon (PPy/CCC) has been carried out under various experimental conditions. Quantity of Ni(II) uptake at 50 mg of activated carbon is 25.75 mg/g for CCC and 29.60 mg/g for PPy/CCC. Adsorption data are modeled with Freundlich, Langmuir and Temkin adsorption isotherms. Thermodynamics parameters, such as <img src='/image/spc_char/delta.gif' border=0>H^o, <img src='/image/spc_char/delta.gif' border=0>S^o, and <img src='/image/spc_char/delta.gif' border=0>G^ohave been calculated and the findings indicate that the adsorption is spontaneous and endothermic. Enthalpy change values range from 8.90 kJ/mol to 23.04 kJ/mol, and based on these values the adsorption of Ni(II) by CCC could be a physisorption. A mechanism involving intra particle diffusion and surface adsorption has been proposed for the adsorption of Ni(II) onto the adsorbent. Adsorbent used in this study is also characterized by FT-IR and SEM before and after the adsorption of metal ions.