Converging synergistic functions into a cationic polymeric network for unparalleled remediation of TcO4− from high-level radioactive wastes

Abstract

Efficient segregation of TcO₄⁻ from high-level radioactive wastes (HLW) is critical for robust nuclear waste management and environmental protection. However, achieving deep decontamination is especially challenging in complex conditions of strong basicity, high radiation, and excessively competitive anions. Herein, we addressed the long-term challenge by modifying the imidazolium core with phenyl, trimethylphenyl, and benzyl groups in a flexible polymer chain, which constructs a precisely targeted microenvironment for selective TcO₄⁻ capture. This custom-engineered material (SCU-CPN-7) exhibits fast kinetics, high adsorption capacity (314.7 mg/g), excellent distribution coefficient (1.3 × 10⁷ mL/g), and remarkable efficiency in TcO₄⁻ uptake under the combining extreme conditions of strong alkalinity (1 M NaOH) and high radioactivity. More importantly, owing to the synergistic effects of the hydrophobic effect, electrostatic affinity, and p-π interactions, SCU-CPN-7 demonstrates exceptional selectivity, capable of almost quantificationally removing TcO₄⁻ in the coexistence of a large excess of NO₃⁻ and SO₄²⁻, leading to an unparalleled uptake performance of TcO₄⁻ from simulated HLW in both batch and dynamic column separation tests.