Study On The Electro-Catalytic Oxidation Treatment Of Organic Wastewaters With TiO₂-Carbon Aerogels Electrodes

Refractory organic substance is one of the most serious pollutants that affect the water environment. Pollution caused by organic substance is not only leads a serious of environmental pollution, but also seriously imperils people's life and health. Among the electrocatalytic oxidation of organic wastewater treatment method, a method of three-dimensional electrode (TDE) has a wide prospect in application of refractory organic pollutants treatment, high electric current efficiency and desired treatment effect. So it has become a hot research recently. However, there are some key problems to be solved such as research and optimization of the electrode. Morever, an agreement about the reaction process of electrochemistry and the mechanism of organic substance have not been reached. Therefore, the method of TDE has great research value and far-reaching significance.TiO2-Carbon aerogels prepared by the resorcinol-formaldehyde (RF) sol-gel with supercritical drying were explored as Particle electrode in the Three-dimensional electrode reactor. TiO2-Carbon aerogels were characterized by powder X-ray diffraction (XRD), electron microscopy (SEM, TEM). The results show the successful doping of the carbon aerogels with Characteristic peaks (anatase) which were 29=25°,38°,48°,54°,62°and the titania distributed in carbon aerogels homogeneously. We selected graphite and stainless steel plates as the main anode and cathode due to its performance and low cost. So the three electrodes form the three-dimensional electrode reactor. The removal of chemical oxygen demand (COD) from wastewater-containing phenol and aniline were investigated using three-dimensional electrode reactor. Factors affecting the removal efficiency were investigated, including reaction time, applied voltage, pH, type of electrolyte, electrolyte concentration and initial concentration of the solution and so on. We also analyzed wastewater quality by UV-Vis spectrophotometry and HPLC and speculated degradation process of organic substance through the data. Simultaneously, we compared the performance and stability of carbon aerogels and TiO2-carbon aerogels by cycle test.The results show that COD removal efficiency decreased with the number of repeated batch runs in our experimental range, but the performance of the TiO2-carbon aerogels is much better than that for the carbon aerogels and the COD removal ration remains more than 90%. When the applied voltage was 12V, the removal efficiency of the chemical oxygen demand (COD) about phenol could arrive at 98.2%. Simultaneously, the removal efficiency of the chemical oxygen demand (COD) about aniline could arrive at 96.3%. We also found that degradation of aniline more easily than phenol. Through the analysis of water samples, it is obvious that a series of oxidation, ring opening reaction occured. Finally, we speculated that the possible degradation process of organic substance.