Anions, Complexing and Salting - Out Agents Effects on the Extraction of Cr (VI) from HCl and H2SO4 Acid Media Using Chloroform Solution of Bis (4-acylpyrazolones)

Abstract

Extraction of Cr(VI) into chloroform solutions of 4-adipoylbis (1- phenyl-3methypyrazolone-5), H2Adp and 4-sebacoylbis (1- phenyl-3-methypyrazolone-5), H2SP were carried out and the effect of the anions, Cl-, SO42-, Br-, I-, SCN-, PO42-, EDTA, Oxalate acetate and tartarate were studied. The results showed that the masking effect of the halides on the extraction of Cr(VI) followed theorder l-<Br-<CI-. This is consistent with the order of increase in electronegactivity of the element and decrease in ionic radius of the ions. The effect of complexing agents such as, PO42-, acetate EDTA, oxalate and tartarate on the extraction of Cr (VI) ions appears to be fairly constant for both H2Adp and H2SP.  The results obtained show that extractions of these metals are increasingly masked as anion concentration increase in the aqueous phase. The extraction of the metal is reduced in the presence of salting-out agent using H2Adp. Better extractions were obtained when H2SP was used as the extractant. This shows that H2SP is a better extractant than H2Adp for Cr (VI).