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

Untreated radioactive iodine (129I and 131I) 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 × 106 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. [Display omitted] • A π-conjugated and hydrogen-bonded charge transfer complex (TCNQ-MA CTC) was prepared. • The TCNQ-MA CTC has a high affinity for iodine due to the aboundant binding sites. • The TCNQ-MA CTC can adsorb I 2 and I 3 - with large capacity and good selectivity. • The TCNQ-MA CTC shows fast adsorption kinetics with the removal rate of 92% in 2.5 min [ABSTRACT FROM AUTHOR]