Study On Electrolytic Treatment Of Electroplated Nickel Wastewater And Cathodic Polarization Curve

Electroplating of nickel as one of the most widely used electroplating process,the wastewater treatment technology has been improved with the improvement of environmental protection requirements.The treatment of electroplating nickel wastewater by electrolysis technology has important research value because of its advantages such as simple process and recycling of heavy metals.However,its application is not mature and needs further improvement and optimization.This paper is based on the simulation of nickel electroplating wastewater and nickel electroplating wastewater as the research object,the effects of different conditions on the treatment effect of Ni²⁺ and cathodic polarization curves,it has important practical significance to the optimization technology of electrolytic treatment of electroplating wastewater.?1?Nickel was used as cathode to treat simulated nickel wastewater by electrolysis.The effects of different conditions on the removal efficiency of single Ni²⁺ were studied by changing the current density,pH and temperature.The treatment effect was characterized by EDTA and electrochemical polarization curves.The results show that the optimum treatment conditions for nickel as cathode are as follows: the current density is 31mA/cm²,the temperature is 25?,the pH is 6.5,electrolytic treatment 1h,and the removal rate of Ni²⁺ is more than 31%.With the smaller Ni²⁺ concentration,the cathodic polarization curve will move down?2?Under the same experimental conditions,the actual electroplating nickel wastewater was simulated and the effect of COD on the treatment of Ni²⁺ was studied.The treatment effect was characterized by EDTA and electrochemical polarization curves.The results show that the current density is 31mA/cm²,the temperature is 25?,pH=6.5,electrolytic treatment 1h,the removal rate of Ni²⁺ is more than 21%,and the removal rate of COD is above 24%.Organic additives in actual electroplating wastewater of nickel in the presence of COD will increase the cathode polarization effect of wastewater,Ni²⁺ removal rate and current efficiency were lower than the simulated wastewater;astewater cathodic polarization curve and simulated wastewater treatment after the initial segment is similar to that of the electrode potential due to lower Ni²⁺ removal rate and lower than simulated wastewater.?3?In addition,iron,copper and zinc were used as cathodic electrolysis to treat the actual wastewater,and compared with the effect of nickel as cathode.The results showed that the potential of hydrogen and low metal due to reduced H+ reduction of Ni²⁺ competition,thus improving the effect of electrolytic treatment.The cathodic polarization curve of the cathode with the larger Tafel constant a value,the lower the initial electrode potential.?4?Zinc was selected as the cathode,the temperature was 25?,the current density was 31mA/cm²,and the distance between the cathode and the cathode was set to 15 cm,pH=6.5,which was used to treat the nickel plating wastewater by 20 h,the removal rate of Ni²⁺ was close to 85%,and the removal rate of COD was over 85%.