Studies On Degradation Of Saity Reactive Dye Wastewater By Electrochemical Oxidation

Dye wastewater has the characteristics of high chromaticity, high pH change and low biological degradability. And it could cause a serious threaten to the nature and human health. However, the general treatment was difficult to meet the national standards. Electrochemical oxidation is high efficiency, low investment and friendly to environment. Because of its advantages, the study is focused on the degradation of dye wastewater by electrochemical oxidation. The main content is as follow:1、The Acid red B dye wastewater was oxidized using graphite as the anode. Under the optimal conditions, the removal rate of COD, ammonia nitrogen and color reached83.60%,91.12%and83.60%respectively.2、The influence of Ce concentration and the plating temperature on properties of modified electrodes were discussed, including crystallite size distribution and Catalytic oxidation ability. PbO2and PbO2modified by Ce were prepared by electrochemical deposition. The crystal size of the modified electrode was smaller than that of PbO2/C, and CeO2was tested in the coating of modified electrode by the analysis of SEM, XRD and XPS. In addition, the catalytic oxidation of the electrode modified by Ce was stronger than PbO2/C by cyclic voltammetry. The efficiency decreased slightly and the surface of Ce-PbO2/C was not occurred desquamating after using for a long time. It showed that the modified electrode has good stability.3、The Acid red B wastewater was oxidized using Ce-PbO2/C as an anode. The influence of influent concentration, voltage, NaCl concentration, initial pH and electrode distance were studied. The removal of colour, COD and ammonia nitrogenrate were99.98%,95.26%,97.78%under the best condition of voltage12V, influent concentration1g/L, NaCl concentration6g/L, initial pH7, electrode distance1cm. The degradation pathway and intermediate were measured based on UV-Vis and GC-MS analyses. The results showed the breaking of azo double bond was occurred at first and formed small organic substances that include benzene or naphthalene ring. Then the intermediates were degraded to organic acids. At last, the intermediate were degraded to H2O and CO2.4、The acid scarlet GR was oxidized using Ce-PbO2/C as the anode. The influence of voltage, pH, concentration of NaCl and reaction time were investigated. Under the best condition, the decolorizing rate, removal of ammonia nitrogen and COD were99.8%,95.45%and90.81%. The substance contained benzene ring and amine was formed and then was degraded to3-ethoxy ethyl propionic acid, formic acid, succinic anhydride and so on. Finally they were degraded into small molecular substances.Above all, the electrode is suitable for electrolysis azo reactive dye wastewater. And the analysis of degradation pathway has laid the foundation of further mechanism research.