Study On The Process Of Dye Wastewater With Electrochemical Catalytic Oxidation

Dye wastewater contains large quantity of unbiodegradable organic substance. The color of it is high and the composition is complex. As one of the points in the degradation of industry wastewater, dye wastewater is difficult to be treated by common methods.Now in the field of wastewater treatment, it is a focus that refractory organic wastewater is to be degraded by electric catalytic oxidation. The hydroxyl radicals generated in electrolysis process can mineralize the contamination and this method has the merit of no second pollution. Active carbon is a porous inert material and has high sorption, so it is regarded as eminent adsorbent carrier. As a semiconductor, titanium dioxide is easy excited to accept or give up a electron. The holes with positive potential at the surface of titanium dioxide particles have large oxidizing ability and can generate hydroxyl radicals in the electric catalysis system. It is widely used as activator in electric catalysis and photocatalytic system. The activator, nanometer titanium dioxide–loaded active carbon was prepared by adsorption-roasting method. A novel electric catalysis system was introduced to treat methyl orange solution, the typical azo dyes, which was used as the simulated dye wastewater. This paper had investigated the effects of activator amount, current density, applied voltage, pH value, electrolyte concentration, electrolysis time and different air-fed modes on COD and color removal rate. Other dyestuff solution, dye wastewater, dye intermediate wastewater were also treated by the electric catalysis system. Four different methods were compared according to the removal rate of COD and color. The experiment results indicated that the electric catalytic oxidation process could efficiently remove and degrade methyl orange. The removal efficiency could be attributed to the oxidation of hydrogen peroxide, hydroxyl radicals generated in electric catalysis system. Furthermore, salicylic acid had been used as a probe to discuss the generation of the hydroxyl radical. A first-order kinetic model on degradation of COD and a first-order kinetic model on removal of color had separately founded according to the experimental data. The two models represented well the experimental test results of methyl orange.