Adsorption of Cu(I1) and Ni(I1) by pelletized biopolymer Chihpin Huang *, Ying-Chien Chung, Ming-Ren Liou Institute of Environmental Engineering, National Chiao Tung University, 75 Po-ai St., Hsinchu. Taiwan 30039 Received 22 March 1995; accepted 25 July 1995 Abstract Chitosan and Ca-alginate, derivatives of biopolymer, were separately prepared from crab chitin and algin in pellet form for adsorption of Cu(I1) and Ni(I1) from aqueous solutions. The capability of these biopolymers was also investigated to remove copper and nickel from aqueous solutions in an immobilization system, along with a comparison made of these biopolymers with other adsorbents. Additionally, the feasibility of alginate/chitosan in pellets to remove nickel ion and nickel cyanide complex from polluted water was investigated. Stabilizing chitosan physically in an alginate support medium was deemed possible, by means of which both free metal and metal cyanide ions could be removed from aqueous solutions in an engineering system. However, the crosslinking reaction during immobilization would result in blocking of some adsorption sites. Keywords: Chitosan; Cu(I1); Adsorption; Biopolymer; Immobilization 1. Introduction Heavy metals at low concentrations are difficult to remove. Chemical precipitation, reverse osmosis, and other available methods become inefficient when heavy metal contaminants are present at trace concentrations in a large volume of solution. Adsorption is one of few alternatives available in such a situation. The use of adsor- bents, e.g., activated carbon, low cost industrial products, and microbial materials, has received extensive attention [ 11. All of these technologies have their inherent advan- tages and limitations. For instance, activated carbon still requires complexing agents to improve performance in removing inorganic matters. Ion-exchange resins are effective but expensive. Among various adsorbents, biosorbents are attracting an increasing amount of interest for its capability to prepare polymers as effective scav- engers of heavy metals [2]. This process is based on the binding of metal ions by the * Corresponding author. Tel.: 886-35-726463. Fax: 886-35-725958. 0304-3894/96/$15.00 0 1996 Elsevier Science B.V. All rights reserved SW1 0304-3894(95)00096-8