Separation of silver from other metal cations using pyridone and triazole macrocycles in liquid membrane systems

• Published in: Analytical chemistry (Washington) 1988-09, Vol.60 (17), p.1694-1699
• Main Authors: Izatt, R. M, Lindh, G. C, Bruening, R. L, Huszthy, Peter, McDaniel, C. W, Bradshaw, J. S, Christensen, J. J
• Format: Article
• Language: English
• Subjects: Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Membranes; Porous materials
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac00168a013

Selective transport of Ag exp + over other metal ions in competitive experiments in bulk and emulsion liquid membrane systems has been accomplished by using macrocycles of the proton-ionizable pyridone and triazole types. The transport of Ag exp + by the pyridone macrocycles involves the cotransport of an anion, while transport by the triazole macrocycles can involve either co-anion transport or the counter transport of H exp + . In particular, the affinity of Ag exp + for the triazole moiety, the excellent fit of Ag exp + into an 18-crown-6 sized cavity, and the presence of only one proton-ionizable site/macrocycle molecule combine to produce highly selective transport of Ag exp + over Pb exp 2+ and Tl exp + with trazolo-18-crown-6 derivatives in membrane systems containing acid receiving phases. Transport of alkali, alkaline-earth, and several transition-metal cations is minimal in similar membrane systems and, hence, selective transport of Ag exp + over these cations is also expected. 32 ref.--AA