Polyacrylonitrile-Poly(m-Phenylenediamine) Composite Membrane for Recovering Gold From Electronic Waste

There are rich precious metal resources in electronic waste. At present, the recycling of noble metals extracted from electronic waste is a hot topic for researchers. In this study, we successfully prepared a kind of polyacrylonitrile-poly(m-phenylenediamine) composite membrane (PAN-PmPD composite membrane) with a smooth surface and a large number of reducing groups by one-step oxidation and hydrogen bonding. The experimental data show that under the optimum adsorption conditions (adsorption time 5 h and pH = 3), the maximum adsorption capacity of the composite membrane for Au(III) reaches 466.45 mg/g, and it can be regenerated by soaking in sodium bisulfite solution. In addition, the PAN-PmPD composite membrane is applicable to the selective adsorption of over 98% of Au(III) in the actual CPU (central process unit) leachate. In the adsorption mechanism, it is revealed that it binds Au(III) majorly through the redox and coordination effect. Therefore, compared with other adsorbent materials, the PAN-PmPD composite membrane has high selectivity and easy operation, and has broad application future in the areas of resource recovery and circular economy.