Facilitated transport of Zn(II),Cd(II)and Pb(II)ions through polymer inclusion membranes with calix[4]-crown-6 derivatives

摘要

Competitive transport of an equimolar mixtures of Zn(II),Cd(II),and Pb(II)ions from aqueous nitrate source phase(c_(Me)=0.001 M,each)through polymer inclusion membranes(PIMs)using calix[4]crown-6 derivatives,as ion carriers,has been investigated.The influence of the group attached type to the calix[4]-crown-6 molecule on the selectivity and efficiency of Zn(II),Cd(II),and Pb(II)transport across polymer inclusion membranes containing cellulose triacetate as the support was studied.The transport selectivity orders for the PIM with 4 and 5 was:Pb(II)>Zn(II)>Cd(II),whereas for 3 was:Pb(II)>Zn(II)>=Cd(II).The metal cations transport results can be explained by their tendency as the Lewis acids in chemical interaction with the bases.The selectivity coefficients of Pb(II)/Zn(II)and Pb(II)/Cd(II)decrease with the hydrochloric acid concentration increase in receiving phase.Also the influence of the plasticizers nature,i.e.o-nitrophenyl pentyl ether(o-NPPE),o-nitrophenyl octyl ether(o-NPOE),and bis(2-ethylhexyl)adipate(DOA)on the ion transport through PIMs is presented.The initial flux of metal ions insignificantly increases in the following order:DOA