Study on Adsorption and Recovery of Heavy Metal Ions, Cd(II) and Pb(II), by Chitin

The adsorption characteristics of Cd(II) and Pb(II) ions has been studied by using chitin as an adsorbent. The pure chitin was obtained from the extraction of red-crab shell dumped by fish factory. Adsorption kinetics of Cd(II) and Pb(II) ions on the chitin reached at the maximum adsorption within two minutes. Adsorbed amounts of heavy metals were pH 7.0>10.5>3.5 in the following order. Adsorption ratio by chitin was 2199% for Cd(II) ion and 2495% for Pb(II) ion. Recovery ratio of Cd(II) ion on the chitin was 2253%, and that of Pb(II) ion was 2273%. The adsorption behavior of these heavy metals was explained well by Freundlich adsorption isotherm.