SPECIATION STUDIES OF CADMIUM-ORGANIC LIGAND COMPLEXES USING ULTRAFILTRATION AND DIFFERENT SOLID SORBENTS

The speciation studies of Cd species in the presence of organic ligands such as humic acid (HA) were investigated based on a combination of physical characterization by size fractionation using ultrafiltration and chemical characterization by retention studies on different solid sorbents. The aim of this study is to distinguish the labilities of complexed Cd-HA among species with different chemical behaviors at different pH conditions. A set of three columns packed with different substrates, namely, a chelating ion exchange resin Chelex-100, an anion exchange resin Dowex l-X8 and C-18 reversed phase was developed. The retention behavior of the complexes was compared according to their labilities onto the substrates as a function of pH. The applicability of the method to synthetic river water (SRW) sample spiked with Cd species in the presence ofhumic acid (HA) was demonstrated