The extraction of Ni2+ from aqueous solutions of various concentrations of SO4 2- ions in buffered media using 1-phenyl-l,3-methyl4- trichloroacetyl-pyrazolone-5 (HTCP) has been investigated. The synergistic effect of butanol on the extraction of the metal was also examined. Ni2+ was quantitatively extracted from solutions by HTCP only at high pH values (5 - 8) over the pH range 0 – 8 studied. However, addition of butanol resulted in a synergistic extraction of Ni2+ up to 97.78% over the range of pH 5.00 – 8.00 from aqueous buffer media containing 0.1M SO4 2- ion concentration. Increased SO4 2- ion concentration resulted in a slight decrease in the extraction of Ni2+ ion due to masking of the metal by the SO4 2- ion. In addition, overall extraction was shifted to higher pH values for extraction into chloroform solution of the ligand for Ni2+ using butanol. The log Kex and pH1/2 of the various extraction systems were determined.
Key words: Extraction, nickel(II), 1-phenyl-3-methyl-4-trichloroacetyl-pyrazolone-5, effect of pH and sulphate ion
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