Packed-bed columns with dye-affinity microbeads for removal of heavy metalions from aquatic systems

A dye ligand Cibacron Blue F3GA, was covalently coupled with polyhydroxyeth ylmethacrylate (PHEMA) microbeads in the 150-200 mum particle size range. T he sorbent carrying 22.3 mu mol Cibacron Blue F3GA per gram of polymer was then used to remove Pb(II), Cd(II), Cu(II) and Zn(II) from aqueous solution s in a packed-bed column system. Heavy metal ion adsorption capacity of the column was investigated as a function of heavy metal ion-bearing solution flow rate and the inlet heavy metal ion concentration. The maximum metal io n uptake values found were: 80.60, 96.98, 78.36, 103.98 mu mol/g polymer fo r Pb(II), Cd(II), Cu(II) and Zn(II), respectively. The heavy metal adsorpti on capacity of the microbeads decreased with an increase in the circulation rate of aqueous solution. The order of affinity based on molar uptake was Zn(II) > Cd(II) > Pb(II) > Cu(II). Removal percentages of heavy metals rela ted to flow time were determined for different flow rates and initial metal ion concentrations. It was observed that PHEMA microbeads carrying Cibacro n Blue F3GA can be regenerated by washing with a solution of nitric acid (0 .05 M). The desorption ratio was as high as 98.5%. (C) 2001 Published by El sevier Science B.V.