Figure 43.4 illustrates the effect of pH on removal of heavy ions by natural clay. The effect of pH on the adsorption of Cu2+ and Ni2+ was investigated at pH values 1-6. The adsorption of these metal ions from aqueous solution is remarkably influenced by the pH values in the range from 1 to 6 (obtained with a pH - meter of Cyber Scan type pH 500, prepared and adjusted by using either HCl acid or NaOH solutions).
The adsorption percentage was increased in the range of pH: 1-4 to reach 96.26% at pH 4 for copper. This maximum is 91.21% at pH 5 for nickel. The pH values 4-6 were chosen as the optimum for studying of all metals in avoidarder to precipitation of metals which limits the process greatly and the adsorption of metal ions on clay is difficult to be quantified at pH greater than 6. Therefore, the pH 4.5 and 5 were selected for all further studies of copper and nickel, respectively.
-■— Cu2+: pH = 4.5 at 324.7 nm Ni2+: pH = 5 at 232 nm
Fig. 43.5 Effect of dosage of Algerian clay on the removal of Cu2+ and Ni2+ (metal concentration: 10 mgL-1; shaking time: 2 h; V: 50 mL; T: 25°C).
Was this article helpful?