Photoelectrochemical treatment of the dye reactive red 198 using DSA electrodes

The study of the oxidation of the dye reactive red 198 on Ti/Ru_0.3Ti_0.7O₂ electrode is presented. Three different techniques were employed: photocatalytic (interaction of UV radiation and electrode surface), electrochemical (application of a constant current) and photoelectrochemical (simultaneous application of a constant current and UV radiation). The effect of temperature (20–45 °C) and current density (5–89 mA cm⁻²) were investigated. No significant temperature effect was observed for the three techniques used. It was observed that at low current densities (5–30 mA cm⁻²) the photoelectrochemical (PhEC) rate of colour and TOC removal is simply the sum of the photocatalytic (PC) and electrochemical (EC) rates. However, as the current density increases, the rate of PhEC removal is much greater. This phenomenon is interpreted as being due to the increased production of O₂, which goes on to interact with the UV radiation and cause the oxidation of the dye.