Efficient removal of ferric ions from aqueous medium by amine modified chitosan resins

The removal of ferric ions was carried out by using crosslinked chitosan resins immobilized with diethylenetriamine (DETA) and tetraethylenepentamine (TEPA) as active moieties. TEPA containing chitosan resin showed higher uptake capacity (3.2 mmol/g) toward Fe(III) compared with DETA containing one (1.4 mmol/g) at 25 °C. Both kinetics and thermodynamic studies of the adsorption process were carried out. Thermodynamic data indicated that adsorption process is exothermic and spontaneous reaction, while the kinetic data indicated that the adsorption of Fe(III) by the investigated resins follows the pseudo second order kinetics. Breakthrough time, critical bed height and durability of resins were estimated from column studies. The critical bed height for the studied resins are 0.2 and 0.05 cm at a flow rate of 1 mL/min and column diameter of 1 cm for DETA and TEPA containing resins, respectively. These parameters indicated that the resin containing TEPA has high efficiency for Fe(III) removal from aqueous media. Desorption of Fe(III) from the prepared resins was efficiently done using thiourea acidified with HNO3.