Degradation of 4-nitrophenol (4-NP) using Fe-TiO2 as a heterogeneous photo-Fenton catalyst

Photocatalytic degradation of 4-nitrophenol was investigated using Fe-doped (1, 3, 5 and 8 wt.% Fe) TiO2 catalysts under UV light irradiation in aqueous dispersions in the presence of H2O2. Photocatalysts with the lowest Fe content (1%) showed a considerably better behavior with respect to the unloaded TiO2 and the catalysts with higher Fe contents. Photocatalytic degradation was studied under different conditions such as amounts of 1% Fe-TiO2 catalyst, H2O2 dose and initial pH of 4-NP solution. The results indicated that about 67.53% total organic carbon of a solution containing 20 mg L−1 4-NP was removed at pH 6.17 by using 4.9 mM of H2O2 and 0.4 g L−1 of the catalyst in a 2-L batch photo-reactor, the complete degradation of 4-NP occurring after 60 min. It was also observed that catalytic behavior could be reproduced in consecutive experiments without a considerable decrease of the UV/Fe-TiO2/H2O2 process efficiency.