Indole functionalized lignin-based aerogel for sustainable uranium extraction and recycle

Herein, a novel indole-modified cross-linked lignin aerogel (INAALGA) was successfully designed and fabricated. The uranium(VI) extraction performance and mechanism of INAALGA were comprehensively investigated. The results demonstrate that INAALGA exhibits excellent extraction capabilities for uranium(VI), reaching equilibrium within 240 min, with kinetics well described by the pseudo-second-order model. At 298 K, the extraction capacity of INAALGA for uranium(VI) reached 694 mg g ‐ 1 , and it maintained a high extraction efficiency of over 83.3 % after three consecutive adsorption-desorption cycles. Practical validation using simulated uranium-containing wastewater confirmed that INAALGA is a highly promising material for uranium(VI) extraction and enrichment. The extraction process involves multiple mechanisms, including complexation, electrostatic interaction and cation-π interactions. In brief, INAALGA demonstrates considerable potential for uranium(VI) remediation and recovery from wastewater. Furthermore, this work not only presents an applicable approach to alleviate the increasingly serious energy crisis via recycling uranium from nuclear wastewater, but also enriches the method of synthesizing N-doped materials for uranium(VI) adsorption.