Reduced Graphene Oxide Membrane for Gold Extraction from Electronic Waste

Graphene-based laminar membranes open new avenues for recovering gold from electronic waste. In this work, we used reduced graphene oxide membranes (rGOMs) as a model system to elucidate how thermal reduction-induced structural changes enhance the gold extraction performance. Interestingly, the rGOM prepared at 180 °C (rGOM-180) exhibits dual interlayer spacings (7.20 and 3.82 Å) and high-density structural defects, leading to optimal gold adsorption capacity. The dual interlayer spacings of rGOM-180 effectively lower the activation energy required for ion migration into narrow interlayer spacings. The high-density structural defects not only strengthen the cation−π interactions between gold ions and rGOM sheets but also act as electron donors, reducing Au3+ to Au0. These facilitate the adsorption of more gold ions on both the inner and outer surfaces of the rGOM. Our work offers important insights into manipulating membrane structures for enhanced gold extraction performance at the nanoscale.