Separation of lead(II) and copper(ii) by plasticizer membranes with sulphur ana-logus of phosphinic acids as carriers

Investigation of selective removal of Pb(II) and Cu(II) from acidic nitrate aqueous solutions using transport across polymer inclusion membranes PIMs was performed. The sulphur analogus of phosphinic acids, i.e. bis(2,4,4-trimethylpentyl)monothiophosphinic acid (1) and tert-butyl(phenyl)- phosphinothioic acid (2) as well as their mixture were incorporated into polymer inclusion membranes composed of cellulose triacetate as a support and o-nitrophenyl octyl ether as a plasticizer. In the experi-ments the transport of Cu(II) across PIM with 1 was rapid and complete, however the lead(II) removal increased with increased membrane saturation. Selective transport of Cu(II) over Pb(II) through PIMs with binary carrier system (1 + 2) was observed; the selectivity order was: Cu(II) >> Pb(II). At tempera-ture of 50C the selectivity coefficient Cu(II)/Pb(II) for membrane with binary carriers was the highest and was equal to 758.