Biosorption of Cd (II) and Pb (II) ions from Aqueous Solutions Using Carissa carandus

ABSTRACT In the present work an attempt has been made to remove Cd (II) and Pb (II) from aqueous solution by using Carissa carandus Stem Bark (CcSB) as an inexpensive biosorbent. Various parameters such as initial metal concentration (5-25mg/L), biosorbent dosages (1-3g/L), pH (2-8) and contact time (30-240min.) having an impact on adsorption efficiency were studied. Equilibrium contact time was found to be 150 minutes in the case of Cd (II) while in the case of Pb (II) it was attained after 210 minutes. The pH (6) was found optimum for adsorption of Cd (II) and Pb (II). These metals show maximum removal capacity at 2.0g/L (adsorbent dosage) and 10-15mg/L (initial metal concentration). The adsorption data were modeled by using both Langmuir and Freundlich classical adsorption isotherm. The data are better fitted by the Freundlich isotherm as compared to Langmuir and the adsorption capacity (Q m ) was found to be 32.84 mg/g and 80.99 mg/g for Cd(II) and Pb(II) respectively