Designing and synthesizing functional recognition ligands:regulation affinity of soft S atom towards Au(I) ion in thiosulfate solution

Abstract

The advancement of fundamental research in adsorption remains a significant hurdle in achieving thiosulfate gold extraction method widespread industrial application. The present study described a design scheme for a functional recognition ligand aimed at adsorption Au(I) in thiosulfate solution, and evaluated its performance as an adsorbent. The soft S atom was selected as the coordinating atom for Au(I) in thiosulfate solution, utilizing a planar conjugated structure to regulate the ligand's configuration and charge distribution, resulting in a new ligand with similar polarizability to Au(I). The newly designed ligand can form a stronger σ−feedback π bond interaction with Au(I) while minimizing ligand steric hindrance. Consequently, the Au(I) recognition was achieved due to the increased Au(I)−complexes' stability. The synthesized ligands−rich adsorbent (TF−O−) and its adsorption mode for Au(I), as determined through characterization and batch adsorption experiments, are in agreement with the theoretical predictions. The gold loading capacity on TF−O− in thiosulfate solution reaches 370.87 mg ∙ g−1 at 25 °C, which is approximately 15 times higher than that of resin and carbon materials. Furthermore, TF−O− has achieved effective anti−anion interference, simple desorption, and efficient regeneration. This study presents a promising design scheme for functional recognition ligand in metallurgical solutions.