POM Constructed from Super-Sodalite Cage with Extra-Large 24-Membered Channels: Effective Sorbent for Uranium Adsorption

A POMs-based
sorbent functionalized by phosphate groups: H33Na14MoV24MoVI2(PO4)11O73 has been
successfully isolated under hydrothermal conditions. The cooperative
assembly of the ring-shaped polyoxometalate structural building unit
{P4Mo6} and MoO4 tetrahedra linkers
gives rise to an unprecedented supersodalite cage containing approximately
spherical cavities with a 8.76 Å diameter. As POMs-based inorganic
material, compound 1 was first applied as sorbent to
adsorb U­(VI) from aqueous solution, exhibiting good stability, high
efficiency, and selectivity. The maximum sorption capacity reaches
325.9 mg g–1, which may capture radionuclides through
cooperative binding of the phosphate groups. The adsorbed U­(VI) could
be nearly drastically eluted when using 0.1 M Na2CO3 and the sorption capacity for U­(VI) slightly decreased 10.16%
through five successive sorption/desorption cycles. This work represents
first application of POMs-based inorganic materials as sorbent to
adsorb uranium from aqueous solution and provides a feasible approach
for the entrapment and recovery of radionuclides.