Study On The Degradation Of Reactive Brilliant Red K-2BP On RuO_x-PdO/Ti Electrode

The waste highly coloured water of texitile industy contains many complex componds and is harmful to environment. So the discoloration of dye waste water is paid great concern by both governments and reaserchers. Photochemical and photoelectrochemical treatments are two advanced oxidation processes. The treatment of dye water with these techonique is under globle attention due to such characters as high efficiency, simple operation and being benign to environment, Developing new kind of electrode is the key factor for the application of electro and photoelectro technology. Recent years, a serie of electrode materials has been used in the treatment and get high efficiency of color removal. Ti-based Metal Oxide Anodes are used widely because of theirs stability, low cost, long lifetime and high efficiency.In our previous work, RuO_x-PdO/Ti electrode showed high catalytic performance in the electro-catalytic oxidative degradation of aniline. In order to expand the usege of the electrode, RuO_x-PdO/Ti electrode is prepared and used in the electro-catalytic oxidation degradation of Reactive Brilliant Red K-2BP using NaCl as the supporting electrolyte. The parameters altering the efficiency of the electro-catalytic oxidation degradation are also investigated and optimized. It is found that under the optimal reaction conditions, that is, pH value, 2; the concentration of NaCl, 0.02 mol/L; and current intensity, 0.25mA/cm²; a color removal of 99.6% within 1 hour can be obtained. The main cause of the discoloration could be attributed to a synergetic effect between the direct oxidation of the electrode and indirect oxidation of free chlorine formed during the electrochemical treatment. The electrode performs well over wide range of temperatures and initial concentration of dye. This showes promise for the application of RuO_x-PdO/Ti electrode in the treatment of dye-polluted water.In order to extend the usage of RuO_x-PdO/Ti electrode in photoelectrochemical process and explore the cause of synergic effect, RuO_x-PdO/Ti electrode is prepared and used in the photoelectrochemical degradation of Reactive Brilliant Red K-2BP. The effects of supporting electrolytes, such as NaCl, NaNO₃, and Na₂SO₄ on the discoloration are studied. Several parameters altering the efficiency of the photoelectrochemical degradation are also investigated and optimized. It is found that under the optimal reaction conditions, that is, pH～6; the concentration of NaCl, 0.02 mol/L; and current intensity, 0.25mA/cm²; a color removal of 91.6% within 30 minutes can be obtained. The main cause of the discoloration can be attributed to a synergetic effect between electrochemical process and photochemical process, that is, to a synergetic effect between active chlorine formed during the electrochemical treatment and HO·, O-, Cl·from active chlorine under photo radiation. The electrode performs well over wide range of temperatures and of initial concentrations of dye. This showes promise for the application of RuO_x-PdO/Ti electrode in the treatment of dye-polluted water.RuO_x-PdO/Ti electrode shows good stabilty and long lifetime. After the electrode being used for 100 hours, the discoloration can still reach 96.2%. The electrode had been studied by XPS, XRD and SEM. The result demonstrates that the active may be small products of RuO₂ and PdO. The decrease of activity is caused by the loss of Ru and Pd element on the surface and Passivation of the titanium substrate.