Abstract:A batch leaching experiment was conducted to compare the use of EDTA-Na2 with the use of oxalic acid (OX) in effect of removing heavy metal pollutants from brownfield soils. Also, a two-step eluting method with EDTA-Na2 and OX was tested in an attempt to find out optimal combination of OX and EDTA. It was found that EDTA-Na2 was quite effective in removing zinc (Zn), lead (Pb), copper (Cu) and nickel (Ni) from the contaminated soil, but not chromium (Cr). In the experiment, the effect of EDTA did not increase with its concentration, however, OX was effective in removing Cr and the effect increased with the concentration OX used, but its effect of removing Zn, Cu and Ni decreased with its rising concentration. Moreover its effect was particularly low on Pb. The two-step eluting technique using OX (0.20 mol L-1 for 2 h) and EDTA-Na2 (0.01 mol L-1 for 2 h) sequentially could remove the heavy metal pollutants simultaneously and was better than the use of EDTA-Na2 or OX individually in removing Zn, Cu, Cr and Ni. Its total removal rate of Zn was 75.21%, of Pb 21.30%, of Cu 59.81%, of Cr 60.72% and of Ni 62.10%. It is more noteworthy that the two-step eluting technique was very effective in removing metals of non-residual form, with removing rate reaching 91.93% for Zn, 57.75% for Pb, 75.33% for Cu, 73.94% for Cr, and 77.99% for Ni. The findings of the study indicate that the sequential elution technique using different combinations of chemical eluents different in capability of removing heavy metals is a high-efficiency method to remedy heavy metal pollutant contaminated brownfield soils.