Posted by Precious metals (PMs), such as gold (Au), palladium (Pd), and platinum (Pt), are invaluable in various energy- and environment-related applications owing to their exceptional physicochemical properties. In this study, a star-shaped, hydrazide-functionalized polymer (poly(acryloyl hydrazide), S-PAcH) was synthesized based on cyclodextrin scaffold and demonstrated that it can be used as a standalone adsorbent to achieve highly efficient, selective, and rapid PM recovery.
S-PAcH was synthesized by growing ∼19 poly(methyl acrylate) (PMAc) linear arms on a β-cyclodextrin (CDx) core via atom transfer radical polymerization (S-PMAc), followed by amination with hydrazine.
a Schematic of the synthesis process of S-PAcH via atom transfer radical polymerization (ATRP) and amination. b Photograph of a S-PAcH(L) aqueous solution (Inset: TEM image of S-PAcH(L)). c Zeta potentials of commercial amine (bPEI and PAAm) and PAcH-series polymers as a function of solution pH. d Photographs of three PM (Au, Pd, and Pt, 200 mg L–1) aqueous solutions (pH = 2) before (top) and after (bottom) the addition of S-PAcH(L) (0.2 g L–1). The magnified photograph shows the Au/S-PAcH(L) precipitates collected by filtration with a polysulfone ultrafiltration membrane. e Hydrodynamic diameter (HR) of the polymers after their addition (0.2 g L–1) to a Au (200 mg L–1) aqueous solution (pH = 2) as a function of contact time. f HR of the Au/PAcH precipitates as a function of rotation speed. The precipitates were formed by allowing contact between the PAcH-series polymers (0.2 g L–1) and the Au (200 mg L–1) aqueous solution (pH = 2) for 24 h. Error bars in (b, e, f) represent standard deviations determined from three replicates.
Shin, S.S., Jung, Y., Jeon, S. et al. Efficient recovery and recycling/upcycling of precious metals using hydrazide-functionalized star-shaped polymers. Nat Commun 15, 3889 (2024). https://doi.org/10.1038/s41467-024-48090-x