| At present, it has been the difficulty and focus of the waste water treatment for the disposal of toxic and biorefractory organics. All the organics in the waste water can not be treated effectively by the current ordinary waste water treatment technology, although they 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. Chlorine phenolic aromatic compounds are the typical representative of hard-degradation and toxic organics, and the o-chlorophenol (2-chlorophenol,2-CP) is one of them. Taking 2-chlorophenol as model pollutant, this paper developed the fundamental study on the electro-oxidation technology for the organics waste water treatment.In the electrochemical method for the pollution control, the study and exploitation of new electrode material has become a very hot subject. Especially, the anode materials related with electrocatalysis characters are being put more attention than else. With the development of theory and practice of electrocatalysis, more and more new high effective catalytic anode materials have been tapped. The composition and preparation method of electrode are the main influence factors on the structure of electro-catalytic electrode, which is important for electro-catalytic characteristics and stability of electrodes. In order to do some fundamental work which may help the electro-catalytic oxidation technology to be actually applied in waste water treatment, In this work, doped Ti based lead dioxide electro-catalytic electrodes were prepared and their disposal effect were estimated by treating organic waste water.Undoped and Fe, Cu doped PbO2/Ti electrodes were preapared by anodic electro-deposition technique at constant potential. The preparation technologies, including the potential and doping concentration have been optimized in this paper. Taking 2-chlorophenol (2-CP) as model pollutant, the electro-catalytic oxidation characteristic of it over the three prepared electrodes were studied adopting the techniques of polarization curve, cyclic voltammetry, Amperometric i-t Curve and AC Impedance. In the 0.1mol/L Na2SO4 aqueous solution, the results of the polarization curve and cyclic voltammetry showed that the sequence of the evolved oxygen potential is Fe-PbO2/Ti>Cu-PbO2/Ti>PbO2/Ti, The precipitation of oxygen is more and more difficult as the evolved oxygen potential is more and more higher. The sequence of oxidation peak current is Fe-PbO2/Ti>Cu-PbO2/Ti>PbO2/Ti, The electrocatalytic of the electrode is more and more better as the oxidation peak current more and more higher. In the 5 mmol/L 2-CP and 0.1 mol/LNa2SO4 aqueous solution, the results of the Amperometric i-t Curve and AC Impedance showed that the sequence of the degradation rate is Fe-PbO2/Ti>Cu-PbO2/Ti>PbO2/Ti, and the electro-catalytic degradation of 2-CP is controlled by the charge spreads. It was found that the degradation of 2-CP was more efficiently on doped PbO2/Ti electrode than on undoped PbO2/Ti electrode, and the Fe-PbO2/Ti electrode had the highest electro-catalytic efficiency.The UV spectroscopic of the electrolyzing reaction showed that the removal rate of 2-CP on the three electrodes is Fe-PbO2/Ti>Cu-PbO2/Ti>PbO2/Ti. Furthermore, the degradation kinetic on the three prepared electrodes of 2-CP was investigated, which should be fit for the first order reaction model. The research on the electrochemical degradation mechanism of 2-CP indicates that the electro-oxidation of 2-CP on the PbO2 electrode is result from the hydroxyl radical on the electrode surface. Of course the mechanism need to be studied thoroughly. |
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