The Generation And Application Of Hydroxyl Radicals In Water Treatment

The degradation process of Rhodamine B, which is refractory to degrade, is investigated with two-dimension-electrode method and three-dimension-electrode method. The results of the research show that when the stainless steel is used as the anode material, which can generate strong oxidation agent, -OH, the results of wastewater degradation are much better than that when the graphite is used as anode material. The effect of cell voltage increase on wastewater degradation is little. The increase of electric current promotes the generation of hydroxyl radical, which enhances the speed of wastewater degradation. The medium of acidity is favorable to the generation of the hydroxyl radicals, so the results of degradation are better than that under neutral and alkali medium. The three-dimension-electrode cell including the particle electrodes is studied, and it is found that plenty of hydroxyl radicals are generated in the three-dimension-electrode system. When the particle electrodes which are prepared by ourself are used to degrade the dyestuff wastewater, it is found the porous particle catalytic electrodes is best for the wastewater degradation. The bigger the surface area of the particle and the proportion of the micropore to the all pore are, the better the effects on the degradation of the wastewater are.In addition, when the porous active carbon flat electrodes, which are prepared by ourself for the first time, are used as the bipolar electrodes to degrade the dyestuff wastewater, the results are better than that in the two-dimension-electrode system, the electrode material, the distance of the electrodes, the cell voltage, the electric current, the ratio of the cathode area to the anode area and the pH value on the results of wastewater degradation are investigated. The stainless steel anode is the best for the wastewater degradation. The different cathode material has little effect on the wastewater degradation. When stainless steel is used as the anode and cathode and the distance of the electrodes is 1mm, best results of the degradation are reached. Thedegradation of the wastewater speed up as a result of the increase of the cell voltage; If the cathode area is unchangeable and the anode area is increased, the results of the degradation grow better; the result of the electrocatalytic degradation get better along with the lower of the pH value; the effect of the electric current on the degradation is small. The highest current efficiency under the optimal conditions of the wastewater degradation is 56.68%, which is equivalently to the highest current efficiency(50%) reached overseas at present.