Solvent extraction studies on Eu (III) from thiocyanate solutions are carried out using various extractants and their mixtures in bezene . The systems involving 4,4,4-trifluoro-1- pheny-1,3-butadione (TPBD) as a synergist in the extraction of europium(III) using di-noctyl sulphoxide (DOSO), Tri-n-octy1 phosphine oxide (TOPO), triphenyl phosphine oxide (TPhPO), 2-thenoyltifluoroacetone (TTA) and their mixtures has been investigated in benzene. At given extractant concentration (pH=3), the extraction of Eu (III) increases with thiocyanate concentration. The slope of the plot log D (where D is distribution coefficient defined as the ratio of concentration of metal in the organic phase to that present in the aqueous phase) against log [SCN-] is nearly 3 indicating the extraction of neutral species in to organic phase. Mixed species of the type Eu(TPBD)3.S and Eu(TPBD)3.2S were obtained with mixtures of TPBD and DOSO/TOPO/TPhPO (where S=DOSO/TOPO/TPhPO) may be responsible for the synergism , where as species of the type Eu(TTA)2.SCN.2S are obtained with mixtures of TTA and (DOSO/TOPO/TPhPO).
