Self-floating COF/chitosan aerogel for light-induced enhanced gold recovery
Weikang Guo, Yufeng Wang, Zhikai Wang, Yingji Zhao, Qin Shuai, Zhaochu Hu, Yusuke Yamauchi, Lijin Huang
Abstract
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.