Decolorization of C.I. Acid Orange 7 (AO7) via TiO2-assisted photocatalysis under UV illumination in the presence of H2O2 has
been investigated. The effect of pH on decolorization efficiency of AO7 was investigated in TiO2/UV/H2O2 process. The
performance of TiO2/UV/H2O2 system was also evaluated by using synthetic dye-bath effluent of AO7. Solar driven TiO2
photocatalysis was found significantly efficient for the decolorization and degradation of AO7. The rates of decolorization and
degradation of AO7 were found to follow pseudo-first order kinetics. The electrical energy consumption of decolorization of
synthetic dye-bath effluent was found to be 4.1 times higher than that of AO7 solution. Similarly, the electrical energy
consumption of degradation of synthetic dye-bath effluent was 2.2 times higher than that of AO7 solution under investigated
conditions. Considering one order of magnitude reduction in AO7 concentration and COD value, the cost of electrical energy for
decolorization and degradation of AO7 solution and synthetic dye-bath effluent of AO7 was calculated.