Transport of Metal Ions Across Bulk Liquid Membrane With MacroCycle Compounds

Abstract

The transport experiments of Pb2+,Cd2+ and Zn2+ metal cations were
performed by dibenzo-18- crown -6 , dicyclo18-crown-6 , kryptofix 2.2.2 and diaza
18-crown -6 using 1,2- Dichtoro ethane , chloroform and carbon tetra chloride as
liquid membrane , The aqueous source phase consisted of 10-3M of Metals nitrate in
10 ml of double distilled deionized water at PH = 5.2 – 5.5 and the receiving phases
consisted of 10 ml double distilled deionizer water at PH = 3.2-3.7 . The effects of
operating conditions , stirring speed , type of carrier structure and solvents in the feed
and strip phase were studied . From the results that the transport rate of Pb2+, Cd2+ and
Zn2+ metal cations can be enhanced by increasing stirring speed but not very high ,
dicyclohexyl-18-crown-6 is the best carrier structure and du to the effect cyclohexhl
which is electron donating group, 1,2- di chloro ethane was found the best set solvent
according to permeability and flux data du to its polarity constants Also , the
transport rate efficiency observed of cations the selectivity of cations is Pb2+ , Cd2+
and Zn2+ which are appreciable with the value of its hydration energy and the
Pearson,s Hard Soft Acid Base principle (HSAB).