Zero-valent iron supported on nitrogen-doped carbon xerogel as catalysts for the oxidation of phenol by fenton-like system.

Nitrogen-free and nitrogen-doped carbon xerogel materials, from urea and melamine precursors, were prepared at different pH and evaluated as adsorbents/catalysts in the removal of phenol. Then, zero-valent iron (ZVI) was supported on these carbon xerogel materials and its activity was again evaluated for phenol removal by adsorption and catalytic wet peroxide oxidation (CWPO). The prepared samples were characterized by N2 adsorption at -196°C, pH at the point of zero charge (pHPZC ) and elemental analysis. The textural properties of the N-free and N-doped carbon xerogels are strongly influenced by pH of the preparation solution and precursor used. The presence of ZVI on all carbon xerogel supports improved the phenol removal efficiency. ZVI supported on urea- and melamine-doped carbon xerogels show a good performance, reaching above 87% phenol conversion after 60 min of CWPO. On the contrary, pure adsorption and CWPO using the same materials without the presence of ZVI gives low phenol removal efficiency. A correlation was found between the activity of ZVI catalysts in CWPO and the N-content of the supports.