Removal of cadmium from aqueous solution by garlic peel

Garlic peel was used as the raw material to prepare the biosorbent by a simple chemically modified process named saponification with alkaline solution. The obtained garlic peel particle was tested to exhibit fairly good affinity to cadmium ions in the aqueous solution. In comparison, its adsorption behavior was also examined for other metal ions including Cu²⁺, Fe³⁺, Zn²⁺, Pb²⁺, and it shows the adsorptive selectivity for metal ions is as follows: Fe³⁺ > Pb²⁺ > Cu²⁺ > Cd²⁺ ≈ Zn²⁺. The adsorption capacity of cadmium on the garlic peel gel is 0.61 mol/kg, or 68.6g/kg, which is potential to be one of the cost-effective adsorbents for the removal of heavy metal ions from aqueous solution.