SELECTIVE PERTRACTION OF PD(II) ACROSS A SOLID SUPPORTED LIQUID MEMBRANE USING THIAMACROCYCLE S-6-PENTANO-36 AS AN IONOPHORE

Thiamacrocycle-facilitated co-transport of Pd(II) from dilute nitrate acidic solutions has been examined across solid supported liquid membr ane (SSLM) deploying S-6-P-36 as the novel ionosphere. Under the optim um conditions, micro amounts of palladium could be effectively transpo rted from a feed (1 M HNO3) solution across an organic thiacrown membr ane into the product side containing strippants like 2 M NH4SCN. Its c oncentration in the source phase decreased as [Pd](f,t)=[Pd](f,o) exp( -K-obs t). The apparent rate constant (K-obs) increased with increasin g carrier concentration and became nearly constant above 0.02 M S-6-Pe ntano-36. With increase in nitric acid concentration from 0.1 to 5 M H NO3, K-obs decreased. A polytetrafluorethylene thin film support coded as TE-35 and toluene as membrane solvent were invariably used. Among the several reagents tested, ammonium thiocyanate served most efficien tly as the strippant. More than 95% of palladium could be readily tran sported from diverse matrices through 0.05 S-6-Pentano-36 into dilute aqueous ammonium thiocyanate strippant in about 6-7 h.