Financial support: This project was sponsored by International Foundation for Science (IFS) in collaboration with COMSTECH (The Committee on Scientific and Technological Cooperation of the Organization of Islamic Conference, Islamabad, Pakistan and INWERDAM (Inter-Islamic Network on Water Resources Development and Management, Amman, Jordania) through Grant No. W/3624-1 to Dr M. Horsfall Jnr.

Keywords: cocoyam, desorption, heavy metals removal, metal recovery, water treatment.

The effects of acidic, basic and neutral reagents on the recovery of Pb²⁺ and Cd²⁺ from metal-loaded biomass of wild cocoyam (C. bicolor) were investigated by eluting the biomass in five successive cycles using 0.01 M HCl, 0.1 M HCl, 0.01 M NaOH, 0.1 M NaOH and distilled water at different contact times. The data showed that the ease of metal ion recovery from metal -loaded biomass by the eluent solutions is of the order 0.01 M HCl > 0.1 M HCl > 0.01 M NaOH > 0.1 M NaOH > distilled water. Over 94% Pb²⁺ and 74% Cd²⁺ of the initially adsorbed metals were recovered by 0.01 M HCl, while < 20% of both metals was recovered by basic reagent. Distilled water recovered less than 9% of both metal ions from the biomass. Macroscopic changes were also observed as the concentration of recovery reagent increased. This study has demonstrated that the selection of a recovery reagent for metal ions on a biomaterial should give consideration to the reusability of the biomass.