Utilizing Natural Liner Materials for Heavy Metal Removal in Simulated Landfill Conditions

Abstract

Inorganic industrial waste landfills have the potential to contaminate subsurface groundwater supplies through migration of leachates down to the water table and into groundwater aquifers, despite the use of compacted low permeability clay or polyethene liners. This paper aims the removal of Cu2+ and Zn2+ in the leachate from an industrial waste landfill using natural materials (natural zeolite, expanded vermiculite, pumice, illite, kaolinite, and bentonite) as a liner material. Cu2+ and Zn2+ concentrations for all treatments decreased during the process. Of all the different natural materials, natural zeolite, expanded vermiculite and pumice, with bentonite, were effective in removing Cu2+ and Zn2+ present in the leachate. However, the use of illite and kaolinite with bentonite as liner materials could be of disadvantage in Cu2+ and Zn2+ removal from leachate. The adsorption kinetic models were also tested for the validity. The second order kinetics with the high correlation coefficients best described adsorption kinetic data. Simulated landfill leaching with water resulted in gradual dissolution of heavy metals and relatively little change in pH. For natural materials, removal percentages of Cu2+ and Zn2+ ions in industrial leachate generally increase in the order: K<I<B<P<EV<NZ. However, the removal amount of the heavy metal ions decreased dramatically when the initial rate of illite and kaolinite increased. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.