Ultrapure gold recovery from electronic waste as nanoparticles immobilized in hydrogel matrix

Abstract

Solid-supported gold nanoparticles possess significant value as economical and eco-friendly catalysts due to their durability and reusability. Conventional methods to synthesize heterogeneous catalysts require the use of expensive gold precursors, diminishing their economic viability. Recovering gold directly as nanoparticles immobilized in a solid matrix from electronic waste (e-waste) provides a promising economic solution. However, the greater abundance of other metal ions in e-waste solutions makes this task challenging, demanding more selective approaches. This study presents a cost-effective one-pot synthesis of gold nanoparticles immobilized in a hydrogel matrix from e-waste solutions, circumventing the need for gold precursors. The fabricated hydrogel exhibits exceptionally selective gold reduction, producing well-distributed and highly pure (23.78 K) gold nanoparticles inside the hydrogel matrix. The fine control in nanoparticle diameters from 22 to 35 nm was achieved by tuning the monomer compositions of the hydrogel. These hydrogel-supported gold nanoparticles demonstrate reusable catalytic properties, indicating their potential sustainability and industrial compatibility. This approach addresses the economic challenges of synthesizing solid-supported gold nanoparticles and offers a sustainable pathway. © 2024 Elsevier B.V.