Anion Exchange Distribution Studies of Some Metal Ions in Aqueous Nitrite and Aqueous Methanol-Nitrite Media

School of Studies in Chemistry, Jiwaji University, Gwalior, M.P.

Manuscript received 10 October 1979, accepted 30 November 1979

Anion exchange equilibrium distribution of fifteen metal ions have been studied in aqueous nitrite and aqueous methanol nitrite media using Dowex-21K in nitrate form. The ions such as Hg(II), Cd(II) and Ag(I), which were expected to form stable metal nitrite complexes gave high K_D values Studies in aqueous nitrite media suggested the following selectivity sequence of common transition and post transition ions for the anion exchanger used.

Hg(II)>Cd(II)>Ag(I)>Pb(II)>Cu(II)>Zn(II)>Co(II) ≈ Ni(II)

Out of the less common metal ions studied uranyl (II) and Ce(III) gave quite high distribution values. Separation possibilities for many metal ions by ion exclusion technique have been suggested.

Use of methanol as a water miscible less polar solvent mixed with water increased the K_D values with increasing methanol percentage in the solution generally suggesting stabilization of metal nitrite complexes in such solutions. Utility of such solvents has also been shown for planning certain useful separations.