Removal of lead (II) ions from aqueous solution using calcium alginate beads

Abstract

The removal of metal ions from wastewaters using biopolymers such as calcium alginate is currently gaining importance in the treatment of industrial wastewaters. The objective of this study was therefore to investigate the capacity of calcium alginate to adsorb Pb(II) ions from aqueous solution. The parameters investigated were the effects of initial solution pH, contact time and initial Pb(II) concentration. Results were fitted to both the Langmuir and Freundlich isotherms. The optimum pH of adsorption was 5.0 while the maximum adsorption was achieved within 60 minutes at initial Pb(II) concentration of 20 mg/L. The experimental results showed that the R² value for the Langmuir and Freundlich isotherms were 0.9868 and 0.8564 respectively. The maximum biosorption capacity Q^o was 26.52 mgg^-1. From the Freundlich plot the value of n, which indicates the sorption intensity, was calculated as 4.15. These results show that calcium alginate is a good adsorbent for the removal of Pb(II) ions from wastewaters.