Turning Electronic Waste to Continuous-Flow Reactor Using Porous Aromatic Frameworks

Extraction of valuable metals such as gold from electronic wastes (e-waste) is regarded as a promising way of environmental remediation; however, this process is still confronted with the cost-ineffective product for normal usages like electronic devices or jewelry. Therefore, there would be merits in directly converting gold from e-waste to materials of higher value, for example, catalysts for pollutant treatment. Herein, a porous aromatic framework (PAF) with cationic sites, named iPAF-7, was synthesized and exhibited rapid extraction of gold from e-waste. Au@iPAF-7 completely converted nitroarenes to arylamines within 10 s at a rate constant of 7.8 × 10-2 s-1, which is much higher than that of any other gold nanoparticle (AuNP) catalysts with solid supports reported so far. Furthermore, considering the limitations and difficulties of operating powder materials, the aerogel monolith incorporating iPAF-7 was successfully fabricated, which retained the excellent gold extraction ability and catalytic activity of its powder form, thus exhibiting its potential application for continuous-flow catalysis of nitroarene reduction.