Extraction of Copper(II)–NTA Chelated Anions from Water with Aliquat 336

Streams containing metals and complexing agents, which are often encountered in industrial and environmental applications, are not easily treated using conventional chemical precipitation processes. A solvent extraction method is thus proposed in this work. The distribution ratios of Cu(II) between kerosene solutions of Aliquat 336 (tri-n-octylmethylammonium chloride) and the water-containing complexing agent NTA (nitrilotriacetic acid) were measured. Experiments were carried out as a function of aqueous pH, the concentration of amine, and temperature. It is shown that the distribution ratios first increased with increasing pH and then decreased with a further increase in pH. The enthalpy of the extraction was determined. Finally, the nonideal behavior of the organic phase is discussed.