2005 Volume 121 Issue 12 Pages 603-607
The extraction of zinc and cadmium from aqueous solutions by long-chain alkyl quaternary ammonium carboxylates, prepared by combination of trioctylmethylammonium chloride (R3R'NCl) and carboxylic (octanoic, decanoic and lauric) acids (R"COOH), in benzene has been investigated in the vicinity of neutral pH. The organic phases were examined by infrared spectral measurements. As a result, it is found that the extraction efficiency is in the order Zn ‹Cd and Zn› Cd with R3R'NR"COO concentrations which are higher or lower than 0.05 mol dm-3, respectively. In addition, the extraction processes for Zn(II) and Cd (II) may be expressed as Zn2+(aq) + 2Cl-(aq) + 3R3R'NR"COO(org)↔(R3R'N) [Zn (R"COO)3] (org) + 2R3R'NCl(org) and CdCl+(aq) + Cl-(aq) + 2R3R'NR"COO (org)↔(R3R'N)2[Cd(R"COO)2Cl2] (org), respectively.
