Fig. 5 illustrates the variation of Cu (II), Co (II) and Cr (III)
removal on the synthesized zeolite at different pH values. rate of adsorption of single metal ions increased with pH.
In fact, the adsorption percentages increased clearly after
pH 5 for all metals.
Copper ions adsorption remains almost constant up to
4, and then increased sharply to 94% adsorption around pH
6. At higher pH, the adsorption percentage was rather slow
and decreased to 91% adsorption at pH 9. A similar behavior was observed for the sorption of chromium and
cobalt ions where the adsorption percentage remains
practically constant up to pH 5 and increase thereafter
sharply. The maximum removal percentage for copper and
chromium respectively were 90 and 71% at pH 6. These
results are similar to results obtained by Abdel Salam et al.
[35] for heavy metal ions sorption onto peanut husk