Fe-clay-plate as a heterogeneous catalyst in photo-Fenton oxidation of phenol as probe molecule for water treatment

• A novel Fe-clay-plate catalyst was prepared.
• Its activity was assayed in the heterogeneous photo-Fenton oxidation of phenol.
• Phenol degradation rate considerably increased in its presence.
• Apparent activation energy was lower than for other catalytic photo-Fenton systems.
• Stability of the catalyst was confirmed after five consecutive reaction cycles.

A novel heterogeneous photo-Fenton plate catalyst was prepared by immobilizing iron species on the surface of natural Tunisian clay. The activity of this structured catalyst was assayed in the degradation of phenol under UV irradiation at two different wavelengths (245 nm, UVC, and 365 nm, UVA, radiation). Phenol removal rate from the aqueous solution always increased in the presence of the Fe-plate catalyst, even under dark-Fenton conditions and for both 254 and 365 nm UV radiation, confirming the efficiency of the prepared catalytic system in the Fenton process. HPLC analysis confirmed a phenol degradation mechanism towards an almost complete mineralization of the organic compound. An apparent activation energy of 48.7 kJ/mol was calculated from the removal experiments performed at different reaction temperatures in the presence of the Fe-plate catalyst. Catalytic activity remains almost unaltered after five consecutive reaction cycles re-using the same Fe-plate. Catalyst stability was confirmed by means of TEM–EDX analysis, pointing to this novel plate catalyst as a promising option as a Fenton heterogeneous catalyst for the mineralization of organic compounds in wastewaters.

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