SELECTIVE REMOVAL OF LEAD IONS BY POLYETHYLENE GLYCOL METHACRYLATE GEL BEADS CARRYING CIBACRON BLUE F3GA

Abstract

Polyethylene glycol methacrylate (PEG-MA) gel beads carrying Cibacron Blue F3GA (42.6 μmol/g polymer) were prepared for the removal of Pb(II), Cu(II), and Cd(II) from aqueous solutions that contained different amounts of these ions (10–100 mg/L) and at different pH values (2.0–7.0). Adsorption rates were high, and adsorption equilibria were reached within 20 minutes. Adsorption of these metal ions on the unmodified PEG-MA gel beads was zero. The maximum adsorptions of heavy metal ions onto the Cibacron Blue F3GA–attached microbeads from single solutions were 23.3 mg/g (112.4 μmol/g) for Pb(II), 12.4 mg/g (110.3 μmol/g) for Cd(II), and 7.0 mg/g (110.2 μmol/g) for Cu(II). When the heavy metal ions competed (in the case of the adsorption from their mixture) the amounts of adsorption were 14.96 mg/g (72.2 μmol/g) for Pb(II), 0.72 mg/g (11.3 μmol/g) for Cu(II), and 1.10 mg/g (9.8 μmol/g) for Cd(II). Under competitive conditions, the system showed high selectivity for Pb(II) ions. The formation constants of Cibacron Blue F3GA–metal ion complexes were investigated through the application of the Ružić method. The calculated values of formation constants were 8.5 × 10⁵ L/mol¹ for Pb(II) dye, 2.5 × 10⁵ L/mol for Cu(II) dye, and 8.2 × 10⁴ L/mol for the Cd(II) dye complex. PEG-MA gel beads carrying Cibacron Blue F3GA can be regenerated through washing with a solution of nitric acid (0.1 mol/L). The maximum regeneration value was as high as 98.5%. These PEG-MA gel beads are suitable for more than 3 adsorption-desorption cycles without experiencing considerable loss of adsorption capacity.

Keywords:

• Polyethylene glycol methacrylate
• Gel beads
• Cibacron Blue F3GA
• Pb(II) removal
• Formation constants

Acknowledgments