  Radionuclides sequestration through adsorption technology has attracted much
attention due to its unique characters such as high removal efficiency, low
cost, and ease of operation. In this work, the interaction mechanism of
N-functionalized Ti2C MXene (Ti2CN2) as a potential adsorbent for the removal
of strontium ions is investigated by using first principles method. Our results
show that surface N atoms are connected to Sr ions by a robust chemical N-Sr
bond, which provides a stronger interaction and greater capacity (1.291g g-1)
of Sr ion adsorption on Ti2CN2 than Ti2C with other surficial groups O, F and
OH. Furthermore, the thermal stability of the adsorption structure of Sr on
Ti2CN2 with full layer coverage at room temperature is verified by using ab
initio molecular dynamics simulations. Our results are expected to provide a
new perspective for the design of MXene materials as adsorbent for
radionuclide.
