Extraction of metals from wastewater serves two vital functions: treating wastewater to meet discharge standards and recovering valuable metals for potential application. In particular, values of precious metals (such as gold, silver and platinum) in wastewater streams from mining, metallurgy, electronic manufacturing and e-waste recycling can be significant and offset the treatment costs. Herein, we report a composite of nanoscale zero-valent iron in ordered mesoporous carbon (nZVI@C) for rapid reduction and immobilization of precious metals. The iron nanoparticles are anchored by the mesoporous carbon frameworks with active sites partially confined in the carbon cavities. This new material possesses a large surface area (~500 m<sup>2</sup>/g) and highly ordered mesopores (~5.2 nm). Small, uniformly dispersed and reactive iron nanoparticles (&lt;16 nm) are obtained for the first time. This material exhibits outstanding performance for gold (10 μg/L) extraction with &gt;99.9% uptake in less than 5 min. The reclaimed gold nanoparticles are small (&lt;6 nm), stabilized by presence of both zero-valent iron and mesoporous carbon, exhibiting a high conversion (~95%) and stability for catalysis. The material thus offers a new strategy for the minimization of aggregation and deactivation of reactive gold nanoparticles. In water, the nZVI integrated with mesoporous carbon can maintain a strong and stable redox condition and offer a promising solution for metal recovery and for catalysis.

Nanoscale zero-valent iron in mesoporous carbon (nZVI@C): Stable nanoparticles for precious metal extraction

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.