Uptake of U(VI) from aqueous media by magnetic Schiff's base chitosan composite

Schiff's base chitosan composite with magnetic properties has been prepared and investigated. The modification process took place through the reaction between chitosan and polymeric Schiff's base of thiourea/glutaraldehyde in the presence of magnetite. The sorption characteristics of the composite towards UO22+ at different experimental conditions were carried out by means of batch and column methods. The composite showed high affinity and fast kinetics for the sorption of UO22+ ions, the sorption capacity reached 2.32 mmol/g at 25 °C. Various parameters such as pH, agitation time, UO22+ concentration and temperature had been studied. The kinetics and thermodynamic behavior of the sorption reaction were defined. These data indicated an exothermic and spontaneous sorption process, and kinetically followed pseudo-second order model, Fickian diffusion low and Elovich equation. The uptake of UO22+ was slightly influenced by the increase of ionic strength. Breakthrough curves for the removal of UO22+ were studied at different flow rates and bed heights. The critical bed height for the studied column was found to be 0.656 cm at flow rate of 4 mL/min. Hydrochloric acid (0.2 M) was used for desorbing UO22+ from loaded composite: desorption yield as high as 97% was obtained.