Efficient capture of iodine in steam and water media by hydrogen bond-driven charge transfer complexes.

Untreated radioactive iodine ( ¹²⁹ I and ¹³¹ I) released from nuclear power plants poses a significant threat to humans and the environment, so the development of materials to capture iodine from water media and steam is critical. Here, we report a charge transfer complex (TCNQ-MA CTC) with abundant nitrogen atoms and π-conjugated system for adsorption of I ₂ vapor and I ₃ ^- from aqueous solutions. Due to the synergistic binding mechanism of benzene/triazine rings and N-containing groups with iodine, special I-π and charge transfer interaction can be formed between the guest and the host, and thus efficient removal of I ₂ and I ₃ ^- can be realized by TCNQ-MA CTC with the adsorption capacity up to 2.42 g/g and 800 mg/g, respectively. TCNQ-MA CTC can capture 92% of I ₃ ^- within 2.5 min, showing extremely fast kinetics, excellent selectivity and high affinity (K _d = 5.68 × 10 ⁶ mL/g). Finally, the TCNQ-MA CTC was successfully applied in the removal of iodine from seawater with the efficiency of 93.71%. This work provides new insights in the construction of charge transfer complexes and lays the foundation for its environmental applications.
Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest.
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