Selective Separation of Hg2+ on Modified Crosslinked Chitosan Beads Enriched with Amine Groups

Sodium tripolyphosphate crosslinked chitosan was prepared and immobilized with pentamine moieties. The samples obtained were characterized by elemental analysis and FT-IR. The adsorption behavior of the samples was studied towards Hg²⁺ using batch and column methods. The adsorption depended on the pH of the medium and was explained to proceed via complex formation and/or ion exchange mechanisms. The uptake capacity was found to be 4.7 mmol/g at pH = 2. Selective separation of Hg²⁺ from a solution containing Pb²⁺, Cu²⁺, Ca²⁺, Zn²⁺, Fe³⁺, and Mg²⁺ was achieved at pH = 1. The values of the kinetics and the thermodynamic parameters of the uptake process were reported. The flow rate of 3 mL/min in column experiments was found to be the most preferable rate. The regeneration of the loaded resin was performed using 0.5 M potassium iodide.