Study On Electrochemical Oscillation In Dye Wastewater Treatment By Electrocoagulation

With the development of printing and dyeing industry,printing and dyeing wastewater treatment has become a major problem.On the one hand is the increase in organic species,on the other hand is a large number of biodegradable substances appear,the traditional biological methods can not meet the actual needs of the printing and dyeing industry,removal of printing and dyeing wastewater technology and methods has become an important research topic in the field of the environment,Electrochemical flocculation as a simple operation,easy to automate and has a method of environmental compatibility to attract the attention of many scholars.In this paper,the effect of voltage on sCOD and DOC degradation was investigated by electroelidation method.The experimental results show that the sCOD of effluent is 1788.2 mg / L,the best degradation effect,to 25%,while the BOD5 / sCOD effluent ratio of 0.28,the biodegradability of the water increased by 10 times.At this time the system of Coulomb efficiency of 13.24%,Coulomb efficiency with the increase in voltage decreases,2 V when the 33.67%.Energy consumption increases with the increase of voltage,4 V when the system energy consumption is 14.04 kWh / m3.Compared to the other voltage set,the comprehensive degradation effect,the Coulomb efficiency and the energy consumption,it is considered that 4 V is the optimum voltage for handling the actual wastewater.For the reasons of this low-pressure and high-efficiency phenomenon,the experimental results show that the low-pressure and high-efficiency phenomena in the process of degradation of methylene blue solution are higher than that of high pressure and low pressure.When the voltage is 2.6 V,the degradation effect was the best,the degradation of methylene blue was 99.9% and the degradation of TOC was 85.3% after 105 min reaction.Studies have shown that this phenomenon may be related to electrochemical oscillations.The electrochemical oscillations of electrocoagulation devices in different electrolytes were studied.First,the potentials of electrochemical oscillations during the anodic dissolution of iron electrodes in different concentrations of electrolytes were determined by cyclic voltammetry.Then,electrochemical workstation The chaotic eigenvalues of the time series are calculated by using the prepared matlab program for the time series of the reaction current in different constant potential modes.The chaos characteristic of the time series is determined by the power spectrum,the correlation dimension,the Kolmogorov entropy and the maximum Lyapunov exponent.Sexual,ie,electrochemical oscillations.The results show that the electrochemical oscillation occurs not only in the process of organic solution,but also in the inorganic solution.Its appearance as long as the iron electrode passivation,and electrolyte solution has nothing to do,but the different electrolytes will affect the electrochemical oscillation potential node.In the 2mol / L sulfuric acid solution,the oscillation potential interval is 1.2 ~ 1.7 V,which is wider than the low concentration sulfuric acid solution,and the oscillation potential is wide.In this interval,the amount of special anodic dissolution is also the highest,reaching 0.6 g,more than 50% higher than the high potential.In the practical application,the sewage treatment process is usually run under neutral conditions.In this paper,based on the understanding of the effect of electrochemical oscillation on the electrochemical flocculation system,the original acid electrolyte is changed to neutral electrolyte sodium sulfate,In order to achieve the same effect as the low pH system.For the high salt system,using the same electrochemical test method,it was finally determined that the electrochemical oscillation occurred in the sodium sulfate system during the dissolution of the iron electrode.The results show that at the same concentration,when the applied voltage is in the oscillation potential interval,the more effective ferric hydroxide floc is produced,and the flocculation effect is also improved by the comparison of the flocculation effect under different external potentials under the same conditions.The better the turbidity removal rate was 88.3%.In this paper,the study of electrochemical oscillation to electrochemical removal of pollutants to provide a way to ensure the effect of treatment at the same time,reduce energy consumption of new ideas.