Technetium Encapsulation by A Nanoporous Complex Oxide 12CaO•7Al₂O₃ (C12A7).

Area of Science:

• Materials Science
• Nuclear Chemistry
• Computational Chemistry

Background:

• Technetium-99 (⁹⁹Tc) is a long-lived radionuclide posing environmental risks.
• Releases stem from nuclear activities like waste processing, accidents, and weapons testing.
• Effective environmental remediation strategies for ⁹⁹Tc are crucial.

Purpose of the Study:

• To investigate the potential of C12A7, a porous inorganic framework, for ⁹⁹Tc capture.
• To evaluate the encapsulation of technetium atoms and dimers within C12A7 using computational methods.
• To assess the performance of both stoichiometric and electride forms of C12A7.

Main Methods:

• Density Functional Theory with dispersion correction (DFT+D) was employed.
• Calculations focused on the interaction between C12A7 framework and technetium species.
• Energetics of single technetium atom and dimer encapsulation were analyzed.

Main Results:

• Both stoichiometric and electride C12A7 forms strongly encapsulate single technetium atoms.
• The electride form of C12A7 demonstrates significantly enhanced encapsulation of ⁹⁹Tc.
• While energetically favorable, a second technetium atom tends to form a dimer rather than occupying a separate site.

Conclusions:

• C12A7 shows promise as a filter material for capturing hazardous ⁹⁹Tc.
• The electride variant of C12A7 offers superior performance for technetium encapsulation.
• Understanding technetium aggregation behavior is key for designing effective capture systems.