A regenerative dual-functional platform combining dendritic silica and anthraquinone amide: advancing seawater lithium detection and recovery with biosensing capabilities

Abstract

Lithium is a vital energy storage material in high demand, but its excess in water bodies poses environmental risks, necessitating rigorous monitoring and remediation. Currently, there are no reports on the simultaneous detection and extraction of lithium from pure aqueous systems. Addressing this gap, a novel functionalized material named MDNS@DAAH has been developed. This material integrates dendritic silica as a substrate with an anthraquinone-based amide, a lithium-specific chelating fluorophore. MDNS@DAAH exhibits selective, turn-on green emission in the presence of lithium ions amidst common oceanic elements like magnesium, sodium, and potassium in pure aqueous settings, with a remarkably low detection limit of 4.9 nM. The turn-on emission in the presence of lithium ions arises from the disruption of the hydrogen-bonding-assisted PET process that leads to the fluorescence recovery of the anthraquinone system supported by DFT studies. Moreover, it demonstrates an exceptional adsorption capacity for lithium, surpassing established adsorbents with a high value of 97.8 mg g⁻¹, along with rapid kinetics and recyclability over multiple cycles. As a fluorescent probe, it enables the biosensing of lithium in the living organism Artemia salina through fluorescence imaging. Additionally, this material is effective for quantifying and extracting lithium from seawater and sea bittern (91.6% recovery). This study showcases a single platform with dual functions for lithium recovery from seawater, offering benefits in recycling, biosensing, and quantification in real seawater environments.