Abstract:The Cu2+ adsorption on Ca-montmorillonite and δ-Al2O3 in the presence and absence of three pesticides, glyphosate, picloram and chlordimeform, was studied. Glyphosate markedly reduced the adsorption of Cu2+ on Ca-montmorillonite by complexing with Cu2+ ions. The higher the mole ratio of glyphosate to Cu2+, the more the decrease of the Cu2+ adsorbed. Glyphosate increased the Cu2+ adsorption on δ-Al2O3 through "bridge" bonding with δ-Al2O3 and Cu2+. The higher the mole ratio of glyphosate to Cu2+, the more the increase of Cu2+ adsorbed on δ-Al2O3. Picloram also decreased slightly the adsorption of Cu2+ on Ca-montmorillonite by means of complexing with Cu2+. However, it did not influence obviously the adsorption of Cu2+ on δ-Al2O3. Chlordimeform decreased the Cu2+ adsorption on Ca-montmorillonite through competing for the adsorption sites with Cu2+ ions while it showed no effect on Cu2+ adsorption on δ-Al2O3.