Analytical Sciences

Highly Selective Transport of a UranylIon through a Liquid Membrane Containing a Lipophilic Ion-Associate ofMethyltrioctylammonium and Hydroxycalix[n]arene-p-sulfonates(n=6,8) as Metal Carriers

Hirotomo KONDO, Masashi NISHIDA, and IsaoYOSHIDA 

Department of Applied Chemistry, Facultyof Engineering, Sojo University, Ikeda-4, Kumamoto 860-0082,Japan

Uranyl ion, UO₂²⁺, inan aqueous sodium hydrogen carbonate solution of pH 4 - 8 (source phase)was simultaneously and selectively transported into a dilute sulfuric acidsolution (receiving phase) through a membrane (chloroform, bulk) containinga lipophilic ion-associate of methyltrioctylammonium ion andhydroxycalix[n]arene-p-sulfonate ion,2_n (n = 6, 8),MTA⁺-2_n, as a metal carrier.The rate of transport increased in proportion to the concentrations ofUO₂²⁺ in the source phase and carrier in the membraneand along with an increase in the temperature of the system. The rate wasalso increased along with an increase in the pH of the source phase. Noneof the other metal ions were transported, or obstructed the transport ofUO₂²⁺, while the presence of large amounts of sodiumhydrogencarbonate and sodium chloride in the source phase interfered withthe transport bycausing a delay in the start of transport.

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