Facile synthesis of magnetic chitosan nano-particles functionalized with N/O-containing groups for efficient adsorption of U(VI) from aqueous solution

The diethylenetriaminepentaacetic acid-functionalized magnetic chitosan nano-particles (DTPA-MCS) were facilely synthesized. The DTPA-MCS exhibited good affinity and fast kinetic for U(VI) sorption due to its high density of N/O-containing groups. The sorption kinetics followed pseudo-second-order equation, whereas the sorption isotherms agreed well with Langmuir model, with the maximum sorption capacity of 0.66 mmol/g at pH 5.0 and 298 K. Thermodynamic data indicated a spontaneous and endothermic sorption process. The U(VI) sorption mainly proceeds through inner-sphere complexation, as evidenced by the slight influence of ionic strength. The DTPA-MCS could be regenerated by 0.40 M thiourea-0.20 M HNO3 and reused for sorption.