American Journal of Chemistry 2012, 2(4): 238-244 DOI: 10.5923/j.chemistry.20120204.09 Equilibrium, Kinetic and Thermodynamics of Biosorption of Lead (II) Copper (II) and Cadmium (II) Ions fromAqueous Solutions ontoOlive Leaves Powder Akl M. Awwad 1,* , Ahlam M. Farhan 2 1 Royal Scientific Society, Princess Sumaya University for Technology, El Hassan Science City, Amman, Jordan 2 Department of Chemistry, College of Science for women, University of Baghdad, Baghdad, Iraq Abstract Biosorption of lead (II), copper (II) and cadmium (II) ions from aqueous solutions onto olive leaves powder has been investigated. The biosorption of lead (II), copper (II), and cadmium (II) was found to be dependent on solution pH, initial metal ion concentrations, biosorbent dose, contact time and temperature. The experimental equilibrium biosorption data were analyzed by two widely used two-parameters, Langmuir and Freundlich isotherm models. The Langmuir model gave a better fit than the Freundlich model. The kinetic studies indicated that the biosorption process of the metal ions followed well pseudo-second-order model. The thermodynamic parameters Gibbs free energy, ∆G ◦ , enthalpy, ∆H ◦ , and entropy, ∆S ◦ were also calculated, and the values indicated that the biosorption process was endothermic and spontaneous in nature. It was concluded that olive leaves powder can be used as an effective, low cost, and environmentally friendly biosorbent for removal of Pb(II), Cu(II) and Cd(II) ions from aqueous solution. Keywords Biosorption, Olive leaves, Lead, Copper, Cadmium, Adsorption Isotherms, Kinetic,Thermodynamic 1. Introduction Heavy metal ions are present in the wastewater of several industries, such as metal cleaning and plating baths, refineries, paper and pulp, fertilizer, and wood preservatives.Different methods have been used on metal content reduction from water and industrial waste such as chemical precipitation, ion exchange, membrane filtration, electrolytic methods, reverse osmosis, solvent extraction and activated carbon adsorption[1-6]. These conventional techniques can reduce metal ions, but they do not appear to be highly effective due to the limitations in the pH range as well as the high material and operational costs. Among these various treatment techniques, activated carbon adsorption[7] is one of the most commonly used due to its high efficiency and easy operation.In recent years, considerable attention has been focused on removal of metal ions from aqueous solution using adsorbents derived from low-cost agro-wastes[8-16]. In the present work,we have studied the potential oflead (II), copper (II) , and cadmium (II) biosorption on a agro material which olive leaves (OL) coming from olive tree waste.Results from this study can be used to assess the utility * Corresponding author: amawwad2000@yahoo.com (Akl M. Awwad) Published online at http://journal.sapub.org/chemistry Copyright © 2012 Scientific & Academic Publishing. All Rights Reserved of live leaves powder (OL)for lead (II), copper (II), and cadmium (II) removal from water and industrial wastewaters. 2. Experimental 2.1. Adsorbent The raw olive leaves (OL) was collected from a local plantation. This agricultural waste was thoroughly rinsed with water to remove dust and soluble material. Then it was allowed to dry at room temperature. The dried waste was grounded to a fine powder in a grinding mill (Retsch RM 100) and sieved to get size fraction < 44 µm, and then dried in an oven at 60 o C for 24 h. 2.2. Materials All chemicals used were of analytical reagent (AR) grade. Stock solutions of 1000 mg/L of lead (II), copper (II) and cadmium (II) were prepared from nitrates oflead, copper and cadmium which was purchased from Fluka AG using double distilled water. Desired test solutions of metalions were prepared using appropriate subsequent dilutions of the stock solution. The range of concentrations of metal ions prepared from standard solution varies between 10 and 100 mg/L. Before mixing the adsorbent, the pH of each test solution was adjusted to the required value with 0.1 M NaOH or 0.1 M HCl.