Study of degradation kinetics of wastewater containing organic colorant by nano photo-catalytic advanced oxidation process (UV/nano-TiO2/ H2O2)

In this research, photocatalytic decolorization and mineralization kinetics and mechanism of simulated wastewater, containing organic colorant, has been investigated by advanced oxidation process (AOP) of UV/nano-TiO2/ H2O2. Acid Blue 92 (AB92), a monoazo acidic class dye, was used as model dye in 40, 60 and 80 ppm initial concentrations. Taguchi method was used to optimize the experiments and estimate the optimized condition (optimized concentration of colorant, pH, time and concentration of oxidant) of degradation. The progress of degradation process has been investigated by measurement of maximum absorbance at visible spectrum of UV/Visible spectra (571 nm for AB92) for each sample. After specifying the optimized condition, the kinetics experiments were carried out in three different pH levels, acidic, neutral and basic. Kinetic analysis of AB92 indicated that the photocatalytic degradation rate is approximately foure order in basic pH. Decreasing of pH level reduced the order of reaction rate equation. Degradation process of AB92 progress was followed through FT-IR and UV-Vis analyses. Results of these analyses helped to select the best suggested degradation mechanism of photocatalytic advanced oxidation process by UV/nano-TiO2/H2O2.