Photoelectric Decolorization Degradation of Direct Orange with Optimization by Response Surface Method

The photoelectric decolorization process of direct orange dye was systematically optimized by single factor experiment and response surface method. The effect of TiO₂ concentration, NaCl concentration, applied voltage, illumination time and other factors on the decolorization effects were discussed. The results showed that under the optimal conditions of TiO₂ concentration of 0.15 g/L and NaCl concentration of 2.85 g/L, the decolorization rate of direct orange solution (pH 7.0) could reach 98.81% while electrolysis at 7.60 V and irradiated for 20 min with 250 W high pressure mercury lamp (main peak wavelength of 365 nm).