Layered titanate nanofibers as efficient adsorbents for removal of toxic radioactive and heavy metal ions from water

Abstract

Titanate nanofibers with two formulas, Na2Ti3O7 and Na1.5H0.5Ti3O7, respectively, exhibit ideal properties for
removal of radioactive and heavy metal ions in wastewater, such as Sr2+
, Ba2+ (as substitute of 226Ra2+), and
Pb2+ ions. These nanofibers can be fabricated readily by a reaction between titania and caustic soda and have
structures in which TiO6 octahedra join each other to form layers with negative charges; the sodium cations
exist within the interlayer regions and are exchangeable. They can selectively adsorb the bivalent radioactive
ions and heavy metal ions from water through ion exchange process. More importantly, such sorption finally
induces considerable deformation of the layer structure, resulting in permanent entrapment of the toxic bivalent
cations in the fibers so that the toxic ions can be safely deposited. This study highlights that nanoparticles of
inorganic ion exchangers with layered structure are potential materials for efficient removal of the toxic ions
from contaminated water.