Abstract
The feasibility of using four novel dithiodiglycolamides (DTDGA) derivatives, namely, N, N, N', N'-tera-octyl-dithiodiglycolamide (TODTDGA), N, N, N', N'-tetra-2-ethylhexyl-dithiodiglycolamide (TEHDTDGA), N, N, N', N'-tetra-n-hexyl-dithiodiglycolamide (THDTDGA), and N, N, N', N'-tet-ra-iso-butyl-dithiodiglycolamide (TIBDTDGA) as agents for the selective extraction of palladium(II) from nitrate solutions was investigated. The extraction of nitric acid was also studied. A systematic investigation has been carried out on the detailed extraction properties of palladium(II) with these extractants from nitrate media. The quantitative extraction of palladium(II) with TODTDGA and THDTDGA from HNO3 is observed at similar to 4 M. The extraction of palladium(II) from an aqueous nitrate solution in the presence of metal ions, such as Zr(II), Nd(III), Fe(III), Mn(II), Sr(II), Ni(II), Cr(II), Pt(IV) and Cs(I) was carried out using TODTDGA and THDTDGA in binary and multicomponent mixtures. The investigated DTDGA showed great extractability and selectivity for palladium than the other investigated metal ions, which showed negligible extraction values. The extraction ability of DTDGA remains almost constant for five successive cycles of extraction/ back-extraction, indicating excellent stability and re-utilization of these extractants.