Comparison of As, Ni, Zn, Cd, and Pb removals using treatment agents

Abstract

The removal of heavy metals, such as As, Ni, Zn, Cd and Pb, onto limestone, starfish, black shale and concrete from wastewater was studied. These materials, with a high capacity for heavy metals, can be obtained and employed as alternative low-cost substitutes. Various parameters, such as the neutralization capacity, changes in pH, redox potential and electric conductivity as a function of time, were quantified. Of the studied treatment agents, concrete showed high neutralization efficiency for acid mine drainage and maintained a pH value above 11. The adsorption of heavy metals was influenced by the compositions of the treatment agents. The experimental results of leaching revealed no significant follow-up release from any of the treatment agents. The results suggest that concrete could be used successfully for the treatment of mixed metal-contaminated wastes.