Removal of Heavy Metals Fe3+, Mn2+, Zn2+, Pb2+ and Cd2+ from Wastewater by Using Rice Straw as Low Cost Adsorbent

Abstract

The adsorption of some heavy metals from wastewater by rice straw was investigated. The adsorption capacity was investigated by batch experiments. The effect of weight of rice straw, contact time, initial metal ion concentration and pH on metal ions removal have been studied. The results showed that the removal percentages increased as the weight of sorbent increased, except for iron. The effect of contact time showed that the removal percentages increased as the contact time increased for all metals expect for iron the removal was decreased. The effect of pH showed that removal percentages increased as pH increased for all metals. In case of initial concentration changing for metal ions (Mn2+ and Cd2+) the removal percentages decreased by increasing initial concentration but for Zn2+ it increased by increasing initial concentration until 40 mg/L then decreased. In case of Pb2+ the removal efficiency was constant until 40 mg/L then decreased by increasing initial concentration and for Fe3+ it was decreased until 60 mg/ L then increased. The adsorption data of metal ions have been described by the Freundlich and Langmuir isotherm models. The order of increasing efficiency of metal ions was Pb(II) > Cd(II) >Mn (II) > Zn(II) > Fe(III).

DOI: 10.5901/ajis.2013.v2n6p85