Construction Of Fly Ash/TiO₂-Fe³⁺ Based Three-dimensional Electrode System And Its Electrocatalytic Degradation Wastewater

In this thesis, based on the characteristic of fly ash and TiO₂, fly ash has been successively modified via activation, acid treatment and alkaline treatment. The modified fly ash was used as support to fabricate the fly ash loaded TiO₂-Fe³⁺ particles. The effect of preparation conditions, temperature and loading layer on the structure and properties were also discussed. Ti/Sn O₂-Ru O₂-Ir O₂-Ce O₂-based dimensionally stable anode?DSA?was fabricated via a facile hydrolysis. The electrochemical properties of as fabricated Ti/Sn O₂-Ru O₂-Ir O₂-Ce O₂ electrode was compared with graphite electrode and titanium plate anode. Multiple techniques, such as XRD, SEM, EDS and CV were employed to investigate the structures, morphology and electrocatalytic properties of as-synthesized DSA electrode. Furthermore, using DSA as anode, graphite electrode as cathode, fly ash/TiO₂-Fe³⁺ as three-dimensional particle electrode, simulated phenolic and ammonia/nitrogen wastewater was treated by a electrocatalytic treatment. The effect of current intensity, electrolytic voltage, initiation p H value, the particles dosage and aeration on the electrocatalytic treatment of wastewater, and the operating conditions was systemic optimized by using the response surface method. The main conclusions are listed as follows:?1?The experimental results indicated that a large number of micropore formed on the surface of fly ash and the specific surface area increased significantly after the Na₂CO₃ activation and HCl acid modification. Comparison to the sol-gel method, the particle prepared using sludge method exhibits more even and higher purification, and thereby processes the better properties for treatment of wasterwater.? 2? Graphite plate performed as the positive anode is easily exfoliated in the process of electrolytic process, and the stability is low. In the electrolytic process of Tiplate, a layer of titanium oxide passive film formed on the surface of anode and suppressed the proceeding of the reaction, which resulting in the zero current phenomenon occurred. However, the DSA anode exhibited the stronger electro-catalysis activity, higher chemical stability and longer longevity than that of pure-Ti plate anode and graphite plate anode.? 3? The experimental results of electro-catalytic oxidation of simulated phenol wastewater treatment results show that the current intensity, the initial p H of waste water,the particle mass have important influence on phenol removal effect, under this experimental condition, the influence of the aeration is not obvious. In the optimal operating conditions of no aeration, the current strength is 1.3 A, the initial p H of wastewater is 4.40, the particle mass is 2.65 g, COD removal rate can reach 69.92%.? 4?The study of electric catalytic oxidation of phenol wastewater degradation simulation shows that the initial p H of the waste water, electrolytic voltage, particle mass have a certain degree impact to the ammonia nitrogen removal effect, when the initial p H of wastewater is 7, the electrolysis voltage is 12 V, the particle mass is 3 g, ammonia nitrogen removal rate is 99.3%; Response surface method to predict the optimal operating conditions is: the initial p H of wastewater is 8.30, the electrolysis voltage is 12 V, the particle mass is 2.75 g, ammonia nitrogen removal rate can reach 99.62%.