Adsorption of uranium by amidoximated chitosan-grafted polyacrylonitrile, using response surface methodology

• Amidoximated chitosan-grafted polyacrylonitrile was used for uranium adsorption.
• Doehlert design of RSM was used to study the adsorption process.
• Experimental values showed good agreement with predicted values.
• CTS-g-PAO had high adsorption capacity (312 mg/g) and removal efficiency (86%).

The amidoximated chitosan-grafted polyacrylonitrile (CTS-g-PAO) was prepared for the adsorption of uranium from water. The effects of pH, concentration of uranium and the solid–liquid ratio on the adsorption of uranium by CTS-g-PAO were optimized using Doehlert design of response surface methodology (RSM). The adsorption capacity and removal efficiency achieved 312.06 mg/g and 86.02%, respectively. The adsorption process attained equilibrium only in 120 min. More than 80% of the absorbed uranium could be desorbed by 0.1 mol/l HCl or EDTA-Na, and CTS-g-PAO could be reused at least 3 times. The CTS-g-PAO and U(VI) ions formed a chelate complex due to FTIR spectral analysis. The surface morphology of CTS-g-PAO was also investigated by SEM. The adsorption process was better described by Langmuir isotherm and pseudo second order kinetic model. Results obtained indicated that CTS-g-PAO was very promising in adsorption of uranium from water.