Abstract

Levels of Pb(II), Cu(II), Zn(II), Mn(II), and Co(II) ion in aqueous solutions were determined by atomic absorption spectrometry (AAS) technique after preconcentration on diethyl dithiocarbamate supported by EDTA modified charcoal from Khaya senegalensis wood. The sorbed elements were eluted with acid and subsequently analyzed. The influence of pH, contact time and initial metal ion concentration by the modified charcoal was investigated. At 90 min contact time the uptake level of metal ions from solution was found to depend on the metal ion-substrate contact time, ion concentration and ion type. The percentage recovery of the metals ions retained by modified charcoal was highest at pH 5. The sorption recovery for the metal ions was within the range of 95.1-99.8%. It was observed that EDTA modification of charcoal significantly improved the percentage recovery of the metal ions. The results obtained from the study showed EDTA modified charcoal to be favourable for preconcentration and removal of heavy metal ions from aqueous solution.

Key words: Preconcentration, removal, heavy metals, modified charcoal, environmental pollution.