Comparative study on batch equilibrium biosorption of Pb2+, Cd2+ and Ni2+ using chemically modified Newbouldia Leavis seed pod: Isotherm studies.

The objective of this study is to investigate the removal efficiency of Pb2+, Cd2+ and Ni2+ by chemically modified Newbouldia Leavis seed pod from aqueous solution under different experimental conditions. In this study, metal ion concentration, temperature and adsorbent dosage were conducted through batch mode experiments. Chemically modified Newbouldia Leavis seed pod was found to possess relatively high sorption capacity for Ni2+ compared to Pb2+, Cd2+. The data obtained from the equilibrium experiment were analysed using Langmuir, Temkin, D-R and Freundlich isotherm models. Among these isotherm models, D-R isotherm mode gave the best interpretation of the experimental data better than Freundlich with high correlation coefficients for the adsorbate. According to the Langmuir model, the maximum uptake capacities (qe mg g-1) of the biosorbent used for Ni2+ , Pb2+ and Cd2+ was 68.966 mg/g, 28.169 mg/g and 29.412 mg/g respectively at 303 K. The results showed that chemically modified Newbouldia Leavis seed pod can be used to remove Pb2+, Cd2+ and Ni2+ form aqueous system.