Fabrication of reclaimable adsorbents without secondary pollution caused by dust pollution is a challenge in the field of nuclear wastewater purification and emergency treatment. In this study, novel core–shell Fe3O4@titanate nanocomposites were successfully developed to meet the demanding requirements for quickly removing the radioactive ions within only a few hours from the simulation nuclear leakage water. Adsorption experiments demonstrate that the Fe3O4@titanate nanomaterials can be regarded as efficient adsorbents with the saturated sorption capacity as high as 118.4 mg/g for Ba2+ ions. And the fast adsorption process can guarantee that the radioactive polluted water can be recovered within only few hours after a nuclear leakage. Moreover, the novel materials could be fully reclaimed by virtue of the magnetic recycling equipment because of their magnetic nature. The results demonstrate the Fe3O4@titanate nanomaterials can be used as a promising emergency radioactive adsorbent after a nuclear leakage.