| At present, it has been the difficulty and focus of the waste water treatment for the disposal of toxic and biorefractory organics that can't be treated effectively by the current ordinary waste water treatment technology. All the organics in the waste water do great harm to the human and natural environment. As one of the highly effective and low-costing methods, the electro-oxidation method, with its special degradation mechanism and capability, has attracted more and more concern and attention of the people. Therefor, in this article, we will develop the fundamental study on the electro-oxidation technology for the organics waste water treatment. Phenol, being extended in the organic waste water, is selected as the simulation pollutant of toxic and biorefractory organics.Firstly, we develop a new type of lead dioxide electrode doped by fluorin. This electrode is made up of four layers: the base is made of titanium plate. And the base is covered with ruthenium and titanium mixed oxide compounds as bottom, at the same time, the mesosphere is composed with a -PbO2, and plating β-PbO2 as the surface layer. Through the voltammetry curve and anode polarization curve testing, compared with Pt electrode, β -PbO2 behaves an excellent catalysis and stability.Secondly, we use this new type of electrode as anode, and regard the stainless steel plate as cathode to degrade stimulant phenol waste water in a no dissepimental electrobath. The factors such as current density, pH, initial phenol concentration, and density of assistant electrolyte are the systematic research in the process of degrading phenol. Phenol and COD removal is increased as the increasing of current density; the suitable condition is 25mA/cm2. There is an optimal condition for assistant electrolyte concentration. The value is 0.05M in the system. Acidic condition is better than neutral and alkaline condition for phenol degradation. Phenol's and COD's wiping off ratio is decreased as increasing the initial phenol concentration, but the absolute wiping off value is increased wholly.Using potentiostat/galvanostat Model 273A, we study the electro-oxidation degradation behaviors and kinetic of phenol on PbO2 and Pt electrodes by cyclic voltammetry and linear potential sweep technology. It is disclosed that oxidation ofphenol on PbO2 electrode occurred mainly in the range of oxygen evolving potential with no phenol oxidative polymerization. So the PbO2 electrode showed the merits of good catalytic activity and steady in the oxidation process. The difference between Pt and PbO2 electrode is result from the oxygen evolving way on the two electrodes. On the PbO2 electrode, being higher oxygen evolving potential, there are many hydroxyl radical on the electrode surface. Phenol can be almost completed by this strong oxidant whose oxidative ability is only lower than fluorin. But no hydroxyl radical on the Pt electrode, phenol discharge directly on electrode surface. This results in many phenoxy-radicals which is easy to polymerize on Pt electrode surface. The risk of electrode fouling is increasing.The kinetics study of phenol electro-oxidation indicates that the electrolyzing oxidation accords with the apparent first-order kinetics law: the oxidation rate constant has linear relationship with the 1.5th power of current density and negative the 0.86th power of initial concentration of phenol. The effect of temperature on degradation reactions is also studied. The activation energy of the reaction obtained through the Arrhenius equation is 5.29KJ/mol, which is far lower than that of common chemical reaction, so that this reaction is more easily to take place.The UV spectroscopic study shows that the electrolyzing reaction of phenol first produces quinone, then the benzene rings will be opened and finally CO2 and H2O are produced.
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