Retracted Article: Selective Uptake of Uranium,Plutonium and Americium on Hydrogen Titanate Nanotubes
Hydrogen titanate nanotubes (HTNT) were prepared by hydrothermal method and characterized by SEM, TEM, XRD. The sorption efficiencies for alpha-emitting radionuclides 239Pu, 233U and 241Am were investigated. All three radionuclides studied were completely taken up by the synthesized HTNT between pH 1.00 to 6.00 from their mCi/L or mg/L feed concentration. The sorption process was sufficiently fast (complete uptake within an hour) and the standard free energy change accompanying the reaction was having very large negative value indicating it to be both thermodynamically and kinetically favourable. The sorption isotherms indicated predominant uptake of the radioactive metal ions in the solid phase of the exchanger at lower feed concentrations and linear Kielland plots with positive slopes indicated favourable exchange of the metal ions by the H+ ions in HTNT with the progress of the reaction. The Kielland plots suggested selective sorption of 233U , 239Pu and 241Am when their equivalent fractions in the solid was greater than 0.02, 0.015 and 5.0 ×10-4 , respectively and it was confirmed for americium uptake with interference studies. Even 5.00 g/L concentration of hydrogen titanate yielded 86 % sorption of 241Am after 15 minute and quantitative sorption after one hour of equilibration. The high Kd values suggest that the nano-titanate is potentially capable of removing americium, plutonium and uranium from large volumes of aqueous solutions.