Adsorptive removal of uranium ions from liquid waste solutions by phosphorylated chitosan

• In this study, Phosphorylated chitosan was synthesized.
• Phosphorylated chitosan used to investigate the adsorption of U(VI) ions.
• The P-chitosan exhibits good adsorption characteristics for uranium (VI).
• The adsorption of uranium on P-chitosan was not a pH dependent.
• Langmuir model describe the adsorption, adsorption capacity was 54.95 mg/g.

The purpose of this work is to take a closer look for the phosphorylation of chitosan and its potential applications for uranium removal from waste effluents. The synthesized P-chitosan has first been characterized using FTIR spectroscopy and scanning electron microscope before and after adsorption of uranium. From the former it is showed that the phosphate groups may be more responsible for the adsorption of uranium. The relevant factors that influence the uranium adsorption onto the phosphorylated chitosan namely solution pH, contact time, temperature, Co-ions, solid–liquid ratio and initial uranium concentration were studied in detail. The obtained results are fitted into the different adsorption isotherms and according to Langmuir adsorption model the uranium adsorption capacity of the synthesized P-chitosan is estimated as 54.6 mg/g. It was also observed from the obtained kinetic data that the pseudo-second order model is more suitable to explain the adsorption kinetics of uranium up on the P-chitosan. Finally the thermodynamic parameters show the adsorption reaction to be a spontaneous process and more favorable at room temperature.