BIOSORPTIVE REMOVAL OF NI (II) IONS FROM AQUEOUS SOLUTIONS USING MAGNIFERAINDICA (MANGO LEAF) LEAF POWDER: ADSORPTION AND CHARACTERIZATION STUDIES

The adsorption behavior of Ni(II) from aqueous solution onto agricultural waste such as mango leaf powder (MLP) was investigated as a function of parameters such as solution pH, initial Ni(II) concentration, contact time, agitation rate and particle size. The Langmuir and Freundlich models were applied to describe equilibrium isotherms using regression analysis. The monolayer adsorption capacity of MLP was found to be 16.62 mg/g. A good agreement (with R2 = 0.9966) between the Langmuir and experimental data was investigated. The Freundlich constant (n) and separation factor (RL) values suggest that the metal ions were favourably adsorbed onto biosorbent. The characterization studies were carried out using Fourier transform infrared spectrometer (FTIR). Pseudo first order and pseudo second order kinetic models were used to describe the kinetic data and the rate constants were evaluated. The result of kinetic study shows that the adsorption of Ni (II) could be described by pseudo second order equation. Complexation between metal ions and binding sites of the biosorbents was the main adsorption mechanism.