DURABILITY OF TWO EXTRACTANTS FOR Pd(II) SEPARATION, THIODIGLYCOLAMIDE AND DI-n-HEXYL SULFIDE: AGAINST A MIXED SOLUTION OF HNO_3 AND HCl

摘要

The extractability for Pd(II) using MOTDA and DHS and their durability against a mixed solution of HNO_3 and HCl was investigated by solvent extraction and FT-IR measurements. Both MOTDA and DHS selectively extracted Pd(II) over Pt(IV) from 0.75 M HNO_3—2.25 M HCl solutions. The extraction rate of Pd(II) with MOTDA was much greater than that with DHS. In the durability test, the extraction percentage of Pd(II) and the FT-IR spectra were measured using MOTDA and DHS after stirring with 0.75 M HNO_3—2.25 M HCl solutions. The extraction percentage of Pd(II) with MOTDA hardly changed during the two-month stirring; however, that with DHS decreased with an increase in the stirring time. The FT-IR spectra showed the sulfoxide formation by the oxidation of the sulfide in DHS, but not in MOTDA. Consequently, it was found that MOTDA is more durable than DHS.