Enhancement of UV-assisted photo-Fenton degradation of reactive orange 4 using TiO2-P25 nanoparticles

A combined homogeneous and heterogeneous photocatalytic decolourisation and degradation of a chlorotriazine azo dye reactive orange 4 (RO 4) have been carried out using ferrous sulphate/ferrioxalate with H2O2 and TiO2-P25 nanoparticles. Enhancement in the photo-Fenton processes has been observed by the addition of TiO2-P25. UV/ferrous/H2O2/TiO2 and UV/ferrioxalate/H2O2/TiO2 processes are found to be more efficient than the individual photo-Fenton and UV/TiO2-P25 processes. The use of ferrioxalate in the combined process is found to be more advantageous. The effects of various experimental parameters such as pH, initial H2O2, Fe2+, Fe3+ and TiO2 concentrations on these combined photocatalytic processes have been investigated. All these parameters strongly influenced the removal rate. The optimum operating conditions of these combined processes are reported.