International Journal of Chemistry; Vol. 4, No. 5; 2012 ISSN 1916-9698 E-ISSN 1916-9701 Published by Canadian Center of Science and Education 35 Modified Saw Dust for the Removal of Lead Cations from Aqueous Media Ismail Abbas 1 , Jinane K. Chaaban 2 & Iyad Karamé 3 1 Chemistry Department, Faculty of Science, Beirut Arab University, Tripoli, Lebanon 2 Faculty of Sciences, Lebanese University, Beirut, Lebanon 3 Department of Chemistry, Lebanese University, Beirut, Lebanon Correspondence: Ismail Abbas, Chemistry Department, Faculty of Science, Beirut Arab University, Tripoli 11-5020, Lebanon. Tel: 961-360-1140. E-mail: i.abbas@bau.edu.lb Received: June 8, 2012 Accepted: June 16, 2012 Online Published: September 20, 2012 doi:10.5539/ijc.v4n5p35 URL: http://dx.doi.org/10.5539/ijc.v4n5p35 Abstract Saw dust modified with chloroethylacetate was prepared. The product was used as an extracting agent for the solid-phase extraction of lead cations from aqueous media. The uptake performance of modified saw dust (MSD) for removal of Pb(II) cations was investigated using batch method. The influences of some experimental parameters like initial concentration of the cation, extraction time, concentration of the saw dust, pH and temperature were studied. Three adsorption isotherms [Langmuir, Freundlich and Dubinin-Redushkevish (D-R)] were used to analyze the equilibrium data. The sorption capacity of modified saw dust was found to be 78.1 mg/g at 298 K from 164 mg/l aqueous solution of lead cation. The mean free energy calculated from D-R model was found to be 15.81 KJ/mol, indicating that chemisorption is involved in the extraction process. The removal of lead cation does not change with increasing temperature. The present method has been compared with the previous methods. Keywords: modified sawdust, Lead Cation, extraction, adsorption isotherm 1. Introduction Rapid industrialization and poor effluent treatment processes in many industries have led to a substantial lowering of water quality that is fed to water bodies. Presence of heavy metals is one of the many factors that lower water quality. The heavy metals cause adverse effects on health, increase environmental toxicity and affect the aesthetic quality of the water (Parab, Joshi, Shenoy, Lali, Sarma, & Sudersanan, 2008). The removal of heavy metal in an effective manner from water and wastewater is, thus, ecologically very important. Common cleaning methods for the removal of heavy metal comprise membrane separation (Chakravarti, Chwodhury, Chakraborty, Chakraborty, & Mukherjee, 1995 ), electrochemical precipitation (Kongsricharoern & Polprasert, 1996), emulsion per traction (Ortiz, Roman, Corvalan, & Eliceche, 2003), ion exchange (Trgo, Peric, & Medvidovic, 2006), preconcentration (Hirata, Honda, & Kumamru, 1989), fertilization (Mandaoker, Dharmadhikari, & Dara, 1994) and adsorption (Danil de Namor & Abbas, 2010 ; Bhattacharya, Naiya, Mandal, & Das, 2008). These methods differ with respect to cost, complexity and efficiency. Lead(II) is a well known highly toxic metal considered as a priority pollutant. It directly enters the water bodies through the effluent discharges including battery, paper and pulp, mining, electroplating, lead smelting and metallurgical finishing industries and caused a marked increase in concentrations. In most countries, lead(II) level of water is limited with the value of 0.05 mg/l. It causes various types of acute and chronic disorders. The safe and effective disposal of Pb(II) containing waste water is a challenging objective for industries because cost effective treatment alternatives are not readily available. A number of adsorbents such as activated carbon (Reed, Arunachalam, & Tomes, 1994), sargassum (K. Park, M. Park, Jang, E. Kim, & Y. Kim, 1999), chitosan (Inoue, Ohto, Yoshizuka, Yamaguchi, & Tanaka, 1997), metal oxide gel (Shubha, Raji, & Anirudhan, 2001), saw dust (Raji, Shubha, & Anirudhan, 1997), humus-boehmite complex (Abraham & Anirudhan, 2001), animal bone powder and ceramics (Abdel-Halim, Shehta, & El-Shahat, 2003) have been used for lead(II) removal. The idea of using various agricultural products and by-products for the removal of heavy metal from solution has been investigated by number of authors (Low, Lee, & Liew, 2000). Natural materials that are available in large