The Study Of Electrochemistry Degradation For Cyanide Wasterwater

Recently,cyanide pollution is becoming serious.Cyanide wastewater is generated in metal processing industry,electroplating industry and dyeing industry.Cyanide wastewater has the characteristics of high toxicity,wide range of contamination,long time pollution and the difficulty dealing with.The traditionally electrochemical method removes cyanide by active chlorine oxidation,which is easy to produce chlorinated by-products,the oxidation rate is slow and the residual chlorine in the water is too high.Therefore,this paper aims to find an efficient,energy saving and environmental method to remove the cyanide wastewater.The concentration of H2O2 influences not only the hydroxyl radical generated by Fenton,but also the singlet oxygen in situ generation by electrochemistry.Therefore,the higher concentration of H2O2 can enhance the cyanide removal rate.A combined electrode of ACF and Ru O2/Ti separated with epoxy resin grid was designed to generate H2O2 efficiently.The oxygen aeration is not needed for the system and the concentration of H2O2 improves four times compared with the original one.Hydrogen peroxide was generated by the cathode reduction oxygen and the oxygen was generated by electrolytic water.The system improved electrochemical efficiency and simplified the reaction device.The combination copper oxides at the anode catalysis and the Fenton-like oxidation in the solution contributed to the cyanide removal.Electrochemical degradation of cyanide wastewater using the Copper/ACF composite cathode(Cu/ACF)and Ru O2/Ti anode was exhibited.The results indicated that the cyanide concentration was lowered from 1.50 to 0.07 m M within 90 minutes at the current density of 50.01 A/m2 and the area ratio of Cu/ACF=1:2.Due to the dissolution of copper plate by the cyanide ions,the copper ions concentration rapidly increased within 15 minutes.Then,it decreased with the efficient destruction of cyanide ions.The system could efficiently and stably remove cyanide.Like the hydroxyl radical,singlet oxygen is a strong oxidant with standard reduction potential.The electrochemical system using Ru O2/Ti as anode and ACF as cathode,with sodium chloride as supporting electrolyte media was efficient for cyanide removing.Effects of the current density and electrolyte concentration on cyanide removal had been examined.The results indicated that the current density and electrolyte media concentration enhanced the cyanide removal rate.In the process of cyanide removing,the p H of the solution decreased obviously.In order to prevent the volatilization of cyanide taking place,the initial p H was selected as 12.0 strictly.This paper has overcome the shortcomings of the traditional electro oxidation and realized two kinds of methods for cyanide removing.This paper not only provides technical support for the cyanide removing,but also expands and enriches the theory of electrochemical purification water.