In this work, 8-hydroxyquinoline is used as the active sites in cross-linked chitosan beads with epichlorohydrin (CT-8HQ). The CT-8HQ material was shaped in bead form and used for heavy metal removal from aqueous solution. The study was carried out at pH 5.0 with both batch and column methods and the maximum adsorption capacity of metal ions by the CT-8HQ was attained in 4 h in the batch experiment. The adsorption capacity order was: Cu 2+ A Ni 2+ A Zn 2+ for both mono-and multi-component systems with batch conditions. From breakthrough curves with column conditions, the adsorption capacity followed the order Cu 2+ A Zn 2+ A Ni 2+ for both monoand multi-component systems. The CT-8HQ beads maintained good metal adsorption capacity for all five cycles with absorbent restoration achieved with the use of 1.0 mol L -1 HCl solution, with 90% regeneration.

Coconut bagasse, an agricultural solid waste was used as biosorbent for the removal of cadmium after modification with thiourea. The adsorption of Cd 2+ was studied at pH 5.5. Langmuir, Freundlich, and Temkin isotherms were used to model the adsorption equilibrium data, and it was found that the system followed the Langmuir and Temkin isotherms. The adsorption capacity of the biosorbent was found to be 35.97 mg g -1 , which is higher or comparable to the adsorption capacity of various adsorbents reported in literature. Kinetic studies showed that the adsorption followed a pseudo-second-order rate model.