Effective adsorption of heavy metal ions (Cu2+, Pb2+, Zn2+) from aqueous solution by immobilization of adsorbents on Ca-alginate beads

Abstract

The performance of adsorbent system consisting of orange peel cellulose (OPC), banana peel cellulose (BPC), orange peel cellulose immobilized Ca-alginate beads (OPCCA) and banana peel cellulose immobilized Ca-alginate beads (BPCCA) for the removal of Cu²⁺, Pb²⁺, and Zn²⁺ from an aqueous solution was tested. The widely used Langmuir isotherm model was utilized to describe the adsorption equilibrium process. OPC and BPC were characterized by SEM and Fourier transform infrared spectroscopy (FT–IR) techniques. The concentration of metal ions was varied in order to obtain optimum concentration level. The effect of pH was studied at different pH values. The role of cellulose in the case of OPC and BPC and the role of alginate in OPCCA and BPCCA were well understood leading to two different mechanisms in native and immobilized cellulose. OPC was found to be a better adsorbent among OPC and BPC, and Cu²⁺ was considered to be adsorbed more effectively than Pb²⁺ and Zn²⁺. The extent of enhancement of adsorption capacity in the case of BPC was greater than that of OPC after immobilization. For the same amount of adsorbents used, OPC and OPCCA showed enhanced activity than BPC and BPCCA.