Removal of Radioactive Heavy Metal Ions From Solution by Superconducting High-Gradient Magnetic Separation With Schwertmannite and Zirconium-Ferrite Adsorbents

Schwertmannite, i.e. iron oxyhydroxysulfate and zirconium-ferrite particles are excellent adsorbents for uranium ions. The magnetic separation characteristics for removal of radioactive ions, i.e. uranium and radium ions, from solution with the adsorbents of synthesized schwertmannite and the zirconium-ferrite particles have been studied. By a 10 tesla superconducting high-gradient magnetic separator, 10 ppb uranium ions in sample solution could be reduced to less than 1 ppb level successfully with the 100 ppm adsorbent addition. Adsorption time dependence for the uranium ions at pH = 7 shows that the effective adsorption sites are located on the particle surface. A different adsorption property due to pH control also suggests that schwertmannite adsorbent can be recycled by the pH control of solution.