Zero-valent iron supported on nitrogen-containing activated carbon for catalytic wet peroxide oxidation of phenol

•Activated carbons were successfully modified with different N-containing precursors.•Urea and EDA treated samples have similar total contents of nitrogen regardless of the pretreatment applied.•The nitrogen content of melamine treated samples is significantly higher.•The iron supported catalysts based on N-containing AC show the highest phenol removal efficiency.

Zero-valent iron supported catalysts were prepared through modifying an activated carbon (AC) support with different nitrogen containing precursors; (ethylenediamine, urea and melamine) and impregnating it with 3 wt% of iron. The supports were characterized by N2 adsorption at −196 °C, elemental analysis (EA), the pH at the point of zero charge (pHPZC) and temperature programmed desorption (TPD). The iron catalysts were also characterized by temperature programmed reduction (TPR). Subsequently, the catalysts were tested in the adsorption and wet peroxidation of phenol. The results from the different characterization techniques demonstrate that the nitrogen-containing groups are successfully introduced into the carbon surface via all the precursors used. The tests of the different modified carbons as adsorbents/catalysts indicated that the adsorption capacity and the efficiency in phenol oxidation are governed by the specific surface area and functional groups present. Both surface chemistry and textural properties of carbons are influenced by the nitrogen source and the type of oxygen functionalities preexisting on the surface. The modified carbon-supported iron catalysts revealed significantly enhanced phenol removal efficiency, reaching over 85% conversion after 3 h, and showed interesting catalytic stability.

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