Removal of free and chelated Cu(II) ions from water by a nondispersive solvent extraction process

The possibility of extraction of free and the ethylenediaminetetraacetic acid (EDTA)-chelated Cu(II) ions from water through a microporous hollow fiber to an organic phase containing extractants LIX64N and Aliquat 336 (a quaternary amine) was studied, in which Cu(II) was simultaneously back-extracted across another hollow fiber to a stripping solutions containing HCl. Experiments were carried out at different flow rates of feed (1.4–4.3 cm3/s), organic (1.2–4.1 cm3/s), and stripping phases (1.4–4.3 cm3/s), and temperatures (298–318 K). It was shown that the extraction rate increased with decreasing feed phase flow rate, but the effect of flow rates of organic and stripping phases was not pronounced under the ranges studied. Mechanism of the mass transfer at each step was discussed and the effect of mutual interaction of the two extractants in the organic phase was also examined. The application potentials of this novel extraction process for this subject appeared to be technically promising.