Optimum Extraction Period.
The efficency of Cu extraction in oranic phase depends on the extraction period.Optimum extractionpeiod was determined according to the procedure described previously by extracting copper from the solutions containing 1 ml of Cu for various periods of time. The amount of Cu dissolved in CCl was determined on basis of measurement of the absorbance using a UV-vis spectrophotometer.After 10 min constant aborbance was obtained and it was constant up to studied period of 30 min. Hence,reaction mixture was extracted at least 10 min for getting maximum recovery.