Thorns, a Novel Natural Plants for Adsorption of Lead (II) Ions from Wastewater Equilibrium, Isotherm, Kinetics and Thermodynamics

Abstract

Thorns, a novel plant material, were found to exhibit excellent adsorption
capacity over a wide range of Pb(II) concentration. It was characterized by Fourier
transform infrared spectroscopy and Scanning Electron Microscopy to support the
adsorption ofPb(II)ions. Effect of different parameters likes pH, contact time ,initial
concentration and different electrolytes was investigated using batch process to optimize
conditions for maximum adsorption. The adsorbent data were analyze using Langmuir,
Freundlich, isotherm equations at 30°, 40° and 50 °C. Thermodynamic parameters such as
standard enthalpy change(∆H°), free energy change (∆G°) and entropy change (∆S°)were
also evaluated and the results indicated that adsorption of Pb(II)spontaneous and
endothermic. Various kinetics models including the Pseudo-first-order kinetics, Pseudosecond-order kinetics and Intraparticle diffusion models have been applied to the
experimental data to predict the adsorption kinetics. Kinetic study was carried out by
varying initial concentration of Pb(II) at constant temperature and it was found that
pseudo-second-order rate equation was better obeyed than pseudo-first-order equation
supporting that chemisorptions process was involved