Experimental assessment of the operative conditions of copper extraction from three contaminated soils.

Column experiments of EDTA extraction of copper from a sandy, a calcareous, and a highly organic soil, were performed. The influence of EDTA concentration, pH, and the flow rate of a flushing solution on copper extraction yield was investigated. Extraction yields of 84.8%, 93.0% and 96.9% were achieved respectively for sandy soil, calcareous soil and highly organic soil, after the injection of a volume of flushing solution equal to 15 pore volumes. TOC measurements performed on the extracted solution showed that, after the extraction phase, the percolation of an equal volume of water was necessary to ensure complete EDTA removal from the treated soils. In addition, results showed that the simultaneous dissolution of calcite consumed approximately 93.6% of the chelant agent when EDTA concentration in the flushing solution was 0.05 M.