In the present stu
dy ion exchange of Pb
2+, Cu
2+, Fe
3+, an
d Cr
3+ on natural Greek clinoptilolite was examine
d in terms of selectivity towar
d the above heavy metals in single- an
d multicomponent solutions in batch systems. Also examine
d are the influence of clinoptilolite on solution aci
dity an
d the effect of aci
dity on the ion exchange process. Clinoptilolite increases solution aci
dity
due to the exchange of H
+ cations with the cations initially present in its structure. H
+ cations shoul
d be consi
dere
d as competitive ones in ion exchange processes, an
d consequently ion exchange of metals is favore
d at high aci
dity values. Cu
2+ an
d Cr
3+ are the most sensitive cations with respect to aci
dity. Selectivity
determination
demonstrates that the selectivity at total concentration 0.01 N an
d aci
dity 2 in both single- an
d multicomponent solutions is following the or
der
Pb2+>Fe3+>Cr3+≥Cu2+. This or
der is set since the first
days of equilibration. However,
Cu2+ shows remarkable changes in selectivity an
d generally its uptake an
d selectivity are increasing with time. On the other han
d selectivity in single metal solutions where aci
dity is not a
djuste
d is following the or
der
Pb2+>Cr3+>Fe3+
der=0 SRC=/images/glyphs/BQ3.GIF>Cu2+.