Gold recovery from aqueous solution using thioamide-functionalized chelating fibers

Currently, the technology for recovering gold from low-concentration solutions remains underdeveloped and represents an urgent issue that requires resolution. This study developed a novel thioamide-functionalized chelating fiber for efficient and selective adsorption of Au(III). The fiber was fabricated by electrospinning a polyacrylonitrile (PAN) solution, followed by crosslinking with diethylenetriamine (DETA) and functionalization to introduce thioamide groups. The optimal adsorbent, prepared with a 15% PAN solution and a PAN:DETA ratio of 1:3, achieved maximum adsorption at pH = 3. It exhibited high adsorption capacity of 710.4 mg/g, excellent selectivity for Au(III) against competing ions, good reusability with >90% efficiency after 4 cycles, and effective enrichment capability from dilute solutions. Mechanistic studies through SEM, FT-IR, and XPS revealed that sulfur-containing groups on the fiber were pivotal, enabling not only chelation with Au(III) but also facilitating its in-situ reduction to Au(I) and Au(0). This work provides a promising strategy for sustainable gold recovery.