Remediation of Uranium-contaminated Groundwater by Sorption onto Hydroxyapatite Derived from Catfish Bones

Hydroxyapatite (HA) was prepared from catfish bones, identified as catfish HA (CFHA), using mechanical and chemical treatment methods. CFHA was characterized by x-ray diffraction (XRD) and scanning electron microscope (SEM) techniques to confirm the presence of HA. The ability of CFHA to remove uranium (U(VI)) from aqueous phase was investigated using both batch and column experiments. Adsorption experiments in batch experiments were carried by varying pH, preparation temperature, and particle size. The data shows that the maximum adsorption occurred between pH5.5 and 7. The adsorption of U(VI) on CFHA was greater at 300 degrees C than at 100 degrees C. Batch data shows that the smallest particles, with maximum surface area, exhibited significant U (VI) removal efficiency. Column experiments were conducted using the smallest CFHA particles at different flow rates and breakthrough profiles were obtained. The scalability of the U(VI) removal process was tested by comparing the performances of columns packed with different CFHA. The results indicated that the reaction scales to the mass concentration of the reactants (CFHA and U(VI)). We also found that at pH7, the CFHA packed in the column has the potential to remove about 3.9 mg of U(VI) per gram. Our study shows that CFHA may be used in permeable reactive barriers for remediating U(VI)-contaminated groundwater plumes.