Effect of transition metal impregnation on oxidative regeneration of activated carbon by catalytic wet air oxidation

• Iron & copper oxide loaded carbons were prepared by incipient-wetness impregnation.
• Higher calcination temperature yielded better metal anchoring on carbon surface.
• Metal oxide loading marginally improved oxidative regeneration of the carbons.
• Iron addition hindered phenol oligomerization, but increased carbon oxidation.
• Copper catalyst showed a significant leaching which promoted a homogeneous reaction.

Impregnation of a commercial activated carbon (AC) with transition metals was investigated to extend its reuse as phenol adsorbent after regeneration by catalytic wet air oxidation (CWAO). Iron and copper catalysts were prepared with varied metal dispersions and oxidation states by using different heat treatments. The main feature of the iron catalysts was to reduce the phenol oligomerization due to oxidative coupling, while the copper catalyst was prone to leaching promoting homogeneous reaction. However their regeneration efficiency was not significantly improved with respect to the starting AC due to an increased adverse effect of CWAO itself on their adsorptive properties.

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