Effect of FAU amount
The sorption of metal ions on the synthesized FAU was
investigated on various amounts of sorbents (from 0.01 to
0.8 g) in constant solution volume (100 mL) at constant room temperature (25 8C) and constant metal concentration
(50 mg/L). The results obtained are illustrated on
Fig. 3, which shows that the removal percentage increased
considerably with the increasing amount of the sorbent up
to 0.05 g/100 mL for all tested metals. This is due to the
larger availability of the exchangeable adsorption sites at
the available greater sorbent surface area [23,26]. However,
further increases in the dose of sorbent did not lead to an
increase in the percentage of removal, which could be
attributed to saturation of the binding sites [27]. Based on
these results, 0.05 g/100 mL was chosen as the optimum
dosage for Cu (II), Co (II) and Cr (III) with a removal
efficiency of 93%, 92% and 68%, respectively. In comparison
with other studies reported in literature for heavy metal
removal, we can concluded that in the present study we
have optimized the zeolite dose by 0.05 g whereas it is 1 g
for zeolite A synthetized from fly ash [28] and 0.8 g for
natural zeolites [2].