Crown-rich alginate aerogel with ultra-high adsorption capacity for lithium-ion via a Möbius strip-inspired “Opening and Re-Ring” strategy

• An eco-friendly crown-rich alginate aerogel was designed and constructed with an ingenious “opening and re-ring” strategy. • The novel aerogel showcases an ultra-high adsorption capacity for Li + (256.91 mg g −1 ). • The simple post-processing method is beneficial for its repurposing application. • This strategy offers a new methodologies for designing efficient crown ether-based adsorbents for lithium ions. Conventional materials for lithium-ion extraction often suffer from significant dissolution loss, the limitation of active sites, low separation efficiency, potential toxicological risks and environmental concerns. To tackle these issues and develop next-generation adsorbent, an innovative adsorbent is designed for delivering superior performance while prioritizing environmental sustainability for lithium-ion extraction in water. Remarkably, inspired by the Möbius strip, this work proposes an ingenious “opening and re-ring” strategy for expanding alginate sugar ring to crown ether ring through an oxidation and an acetal reaction with the ion template imprinting technology. This innovative process results in the development of a novel environmental-friendly and efficient Li + adsorption material. The crown-rich ether alginate aerogel showcases an ultra-high adsorption capacity up to 256.91 mg g −1 for Li + with excellent reusability and selectivity. More importantly, a proposed simple post-processing method is also beneficial for its repurposing application. Adsorption kinetics and thermodynamics reveal that the adsorption behavior is a complex mechanism involving both physical and chemical adsorption. The successful preparation of the novel adsorbent from renewable polysaccharide polymer with outstanding adsorption performances underscores the highly efficiency and sustainability. This study offers a valuable insights and new methodologies for designing efficient crown ether-based adsorbents for lithium ions from water.