Process Biochemistry40(2005)

1293–1299

Removal of Pb(II)from aqueous solution using carbon

derived from agricultural wastes

R.Ayyappan a,A.Carmalin Sophia b,K.Swaminathan b, ,S.Sandhya b

a Sri Ramachandra Medical College and Reasearch Institute(SRMC and RI),Porur,Chennai600116,India

b National Environmental Engineering Research Institute(NEERI)CSIR Complex,Taramani,Chennai600113,India

Received23December2003;accepted16May2004

Abstract

Batch adsorption studies were conducted to study the feasibility of using carbon derived from agro waste materials viz;pith,bagasse and saw dust for the puri cation of wastewater containing Pb(II).The effects of initial metal concentration,contact time,pH and adsorbent dose on the removal of Pb(II)were studied.Among the three adsorbents studied,carbon derived from pith showed better removal than the other adsorbents.Kinetics of removal of Pb(II)was studied using Lagergren rate plots and diffusion phenomena was analyzed using Weber and Morris intra particle diffusion plots.The applicability of the data was analyzed by Langmuir and Freundlich isotherm.Desorption of Pb(II) from the sorbed carbon was achieved by eluting with0.1M HNO3.Carbon was retrieved by washing with0.1M CaCl2solution and reused.©2004Elsevier Ltd.All rights reserved.

Keywords:Adsorption;Pb(II);Pith;Saw dust;Bagasse;Langmuir isotherm;Freundlich isotherm

1.Introduction

Heavy metals are known to be detrimental to the living beings.They are important contaminants of liquid wastes discharged from a number of industries such as electro-plating,dyes and dye intermediates,textiles,tanneries,oil re neries,electroplating,mining,smelters etc.The most common toxic metals found in industrial wastewater are Cr, Ni,Mn,Hg,Cd,Pb,Cu and Zn[1,2].It has been observed that increased concentration of heavy metals in the aquatic environments can cause phyto toxicity,bio-concentration and bio-magni cation by organisms.Pb(II)is a metal,which could be considered to be an environmental concern[3]. The problem of Pb(II)pollution due to use in Pb service pipes,particularly with soft water was the rst recognized metal pollution.Other sources of Pb(II)pollution are battery industry,auto-exhaust,paints,etc.The maximum allowable concentration of Pb(II)in drinking water is0.1mg dm 3.

Corresponding author.Tel.:+91-44-22541964;fax:+91-44-22541964.

E-mail address:kanchana74in@yahoo.co.in(K.Swaminathan).Major health effects due to Pb(II)poisoning are nervous and renal breakdown,weakness,headache,brain damage, convulsions behavioral disorders and constipation.

Removal of heavy metal bearing industrial ef uents has become one of the primary challenges of wastewater treat-ment.The most widely used technique for the removal of dissolved heavy metals involves the process of neutralization and metal hydroxide precipitation.One of the shortcomings of this technique is the disposal of metal containing sludge arising out of the precipitation process.Hence there is a need for developing economic and eco-friendly methods for waste minimization and ne tuning of the wastewater.In recent years,the most promising alternative methods for removal of metal ions use the sorption by waste materials.Marshall and Champagne[4]evaluated the by products of soyabean and cottonseed hulls,rice straw and sugarcane bagasse as metal ion adsorbents in aqueous solutions.At a sub saturating con-centration of metal ion(100mg dm 3),soya bean and cot-tonseed hulls adsorbed high levels(95.6–99.7%)of Cr(III), Co(III),Cu(II),Ni(II),and Zn(II).Vazquez et al.[5]have found that pretreated Pinus pinaster bark was an excellent ad-

0032-9592/$–see front matter©2004Elsevier Ltd.All rights reserved. doi:10.1016/j.procbio.2004.05.007