Microporous Framework (Nb, Fe)-Silicate with Much Potential to Remove Rare-Earth Elements from Waters

Abstract

Nanoparticles of a new small-pore metal silicate formulated as Na2.9 (Nb1.55 Fe0.45 )Si2 O10 ⋅ xH2 O and exhibiting the structure of previously reported Rb2 (Nb2 O4 )(Si2 O6 ) ⋅ H2 O have been synthesized under mild hydrothermal conditions. Replacement of the bulky Rb+ by smaller Na+ ions was accomplished by stabilizing the framework structure via partial occupancy of the Nb5+ sites by Fe3+ ions. Exploratory ion-exchange assays evidence the considerable potential of this new silicate to remove rare-earth elements from aqueous solutions.