Extraction of uranium(VI) with binary mixtures of a quadridentate Schiff base and various neutral donors

Liquid-liquid extraction of uranium(VI) with the binary mixture of quadridentate Schiff base, bis-salicylidene ethylene diamine (H2Salen) (H2A) and neutral donors viz., triphenyl arsine oxide (TPAsO), triphenyl phosphine oxide (TPPO) and tri-n-octyl phosphine oxide (TOPO) has been studied. The extraction order in the equilibrium pH range 2.5 to 5.5 is found to be bis-salicylidene ethylene diamine < bis-salicylidene ethylene diamine + triphenyl phosphine oxide < bis-salicylidene ethylene diamine + tri-n-octyl phosphine oxide < bis-salicylidene ethylene diamine + triphenyl arsine oxide. The composition of the extracted species derived from slope analysis seems to be of the type (UO2A·2TOPO) and (UO2A·2TPPO).