Efficient adsorptive removal of low concentration fluoride ions from water by cellulose beads with trapped CeO2 nanoparticles

The high electronegativity and solubility of fluoride ions (F-) in water at low concentrations pose challenges for their treatment and recovery. To effectively adsorb F-, cellulose beads with trapped CeO2 nanoparticles (CeO2@CBs) were fabricated from a NaOH/urea aqueous solution by the optimal extrusion dropping technology. The CeO2@CBs exhibited a maximum removal efficiency of 99.15% for 10.0 mg L-1 F- at 45°C, pH=3.0 and an adsorbent dose of 1.0 g. The CeO2@CBs were characterized using SEM-EDS, FT-IR, XRD, and XPS. These findings demonstrate that CeO2 nanoparticles were uniformly entrapped in cellulose beads and reveal that the removal mechanism involves anionic exchange and electrostatic attractions between protonated hydroxyl on CeO2@CBs surface and F-. The results show that the anion competition sequence that affects the F- adsorption efficiency was Cl−