Iron-doped titanium lithium-ion Sieves@Sodium alginate-enhanced carboxymethyl cellulose aerogels: A synergistic leap in adsorption and sustainability

Extracting lithium from brine has become one of the most direct and urgent solutions to address the current shortage of lithium resources. The titanium-based lithium-ion sieve (HTO-LIS) is notable for its stable structure, easy preparation, and environmental friendliness. However, the adsorption capacity of HTO has reached a bottleneck, and the serious aggregation phenomenon and low recovery efficiency caused by its powder form also urgently need to be addressed. By doping trace amounts of Fe into HTO, the number of oxygen vacancies can be increased and thus promote ion diffusion, resulting in the increasement of adsorption capacity by 33.8%. More significantly, the introduction of sodium alginate (SA) and carboxymethyl cellulose (CMC) as substrates not only significantly enhances the structural stability of the composite material, but also synergistically constructs a unique polymer network structure that endows the aerogel with outstanding resistance to acid-base erosion, ensuring its integrity under harsh conditions. CMC, with its exceptional swelling properties, significantly enhances the aerogel's surface area and promotes efficient, uniform dispersion of HTO, playing a pivotal role in enhancing adsorbent performance. The optimal adsorbent, 0.03Fe/HTO@SC13, exhibits a maximum adsorption capacity of 42.45 mg g −1 and retains 95.8% capacity after six cycles.