A Study on Heavy Metals Removal in Aqueous Solution Using Autoclaved Chitosan

고온·고압 처리한 키토산을 이용한 수중의 다양한 중금속 제거에 관한 연구

Removal of heavy metal ions (Cd²⁺, Cr³⁺, Cu²⁺, Pb²⁺) by several chitosans was studied and the molecular weight of chitosan was investigated in order to examine the effect of autoclaving. Chitosan were divided into 3 groups (A type, controlled chitosan; B type, autoclaved for 15 min; C type, autoclaved for 60 min). The heavy metal removal capacity and rate of B type chitosan were higher than those of A type and B type chitosan. The molecular weight of chitosan was decreased by the increase of autoclaving time. Therefore, the heavy metal capacity was not well correlated to the molecular weight. Freundlich and Langmuir isotherm was determined from the experimental results of equilibrium adsorption for individual heavy metal ions on chitosan. Langmuir isotherm was well fitted to this experimental data. The heavy metal removal capacity of B type chitosan was in the order of Pb²⁺ > Cu²⁺ > Cd²⁺> Cr³⁺.