A well-performing N, S double doping-carbon/metal composite catalyst prepared from used adsorbent for highly efficient degradation of floatation reagents

The carbon/metal catalyst has gained increasing attention due to its outstanding properties such as high acti-vation capacity and environmental friendliness, while the nonmetallic heteroatom doped into the carbon matrix could further improve its performance. This study prepared a well-performing N, S double doping-carbon/metal composite catalyst by calcinating the spent metal-based adsorbents for organics. The composite catalyst showed improving catalytic performance with a carbon-wrapped Fe and Mn particle structure. For the degradation of 100 mg/L butyl amine (BA), such the composite catalyst delivered a high removal efficiency of 90% within 30 min in the presence of 0.2 g/L oxidant and 0.4 g/L catalyst at 25 degrees C and original pH value. Reactive species including SO4 center dot-, center dot OH, O2 center dot-and 1O2 contributed to the decomposition of BA molecules. In-depth mechanism exploration has shown that the carbon networks could serve as the electron-transfer mediator to accelerate the degradation rate and enhance the anti-interference ability of the degradation system. At the same time, the generation of metal-free active sites of N and S also assisted the BA degradation, in which pyrrole N, S22-and Sn2-with stronger reducibility played crucial roles in the degradation process. This study has provided new insight and a novel approach for reusing exhausted environmental remediation materials to construct efficient advanced oxidation catalysts.

Automated summary

In this study, a N, S double doping-carbon/metal composite catalyst was successfully prepared by calcinating spent metal-based adsorbents. The composite catalyst exhibited improved catalytic performance, with carbon networks serving as the electron-transfer mediator and the metal-free active sites of N and S assisting the degradation reaction.