Removal of heavy metal ions from municipal solid waste leachate using coal fly ash as an adsorbent

The purpose of this study was to investigate the possibility of the utilization of coal fly ash as a low cost adsorbent material for the adsorption of heavy metal ions (Zn, Pb, Cd, Mn and Cu) present in the municipal solid waste leachate. Batch experiments were conducted to determine the effect of contact time and fly ash dosage on adsorption of heavy metals. Experimental data were evaluated to find out kinetic characteristics of the adsorption process. The isothermal data could be well described by the Freundlich adsorption model. Kinetic parameters of adsorption such as the pseudo first-order constant, pseudo second-order constant and the intraparticle diffusion rate constant were determined. The fly ash concentration required to achieve maximum heavy metal removal was found to be 2 g/L with the removal efficiencies of 39%, 28%, 74%, 42% and 71% for Cu. Mn, Pb, Zn and Cd respectively. The results of the study demonstrated that the fly ash could be used as an effective low cost adsorbent for the removal of heavy metal ions from municipal solid waste leachate. (C) 2009 Elsevier B.V. All rights reserved.