Self-floating COF/chitosan aerogel for light-induced enhanced gold recovery

Covalent organic frameworks (COFs) have attracted significant attention as photostimulus-responsive adsorbents for selective gold (Au) recovery. However, their practical scalability is hindered by issues such as particle agglomeration, high costs, and limited light utilization efficiency. Herein, a cost-efficient self-floating COF/chitosan (CS) aerogel is developed that significantly enhances gold recovery efficiency under light irradiation. The incorporation of CS not only reduces the cost, but also endows the resulting COF/CS aerogel with self-floating ability, accelerating the utilization efficiency of light. Benefiting from synergistic effects of coordination interaction, chemical reduction, photothermal, and photocatalytic reduction, this new COF/CS aerogel achieves a high adsorption capacity of 2152 mg g −1 and fast equilibrium kinetics. In addition, the aerogel demonstrates excellent selectivity in recovering gold from real electronic waste (e-waste) leachates. Furthermore, the capture mechanisms of Au(III) by the resulting COF/CS aerogel are verified by spectroscopic and electrochemical analyses. This study underscores the significant potential of the self-floating COF aerogel as a practical solution for the light-induced enhanced extraction of gold from e-waste, positioning it for large-scale applications in sustainable resource management. • A self-floating COF/chitosan aerogel is developed and achieves high Au(III) recovery from e-waste via synergistic photothermal and photocatalytic effects. • Cost-effective integration with chitosan imparts self-floating ability and enhanced light utilization for fast and selective gold recovery. • Mechanistic insight reveals multi-pathway gold capture involving N-coordination, chemical reduction, and photoinduced electron transfer.