| With the continuous development of the electronic industry,the pollution caused by micro etching wastewater was more and more serious.In recent years,researchers had done a lot of research on the treatment methods of micro etching waste liquid,in which electrochemical regeneration technology gradually developed,the advantages of this method is energy saving,small pollution,low cost,can make waste liquid regeneration.Therefore,this study will use electrochemical method to regenerate ammonium persulfate etching wastewater.In this project,electrochemical method was used to regenerate ammonium sulfate micro etching waste liquid and reuse d in etching production.The cathode material was used to reduce the copper ion in waste liquid to 5 g/L and to increase the ammonium persulfate to 120 g/L by using anode material.The electrolytic time and maximum current utilization rate of copper ion an d regenerated ammonium sulfate were explored by optimizing electrolytic conditions.The change of etching rate and the utilization ratio of cathode and anode current of regenerated etching waste liquor with different cycle times were investigated in several cycles of regeneration and etching.The synchronous regeneration was realized by the cation membrane,and the current density was optimized and etched to compare the current utilization of the synchronous and unsynchronized cathode and anode.The copper ion in waste liquid was reduced to 5 g/L by using cathode under different electrolysis conditions.The optimum conditions were determined by measuring the concentration of copper ion and comparing the current utilization rate in electrolysis.The optimal conditions: selection of copper cathode materials,titanium mesh selection of anode material,ammonium persulfate dosage concentration 20 g/L,ammonium sulfate dosage was 98.75 g/L,the dosage of copper ion concentration was 25 g/L,the volume fraction of sulfuric acid was 3%,the current density was 66 m A/cm2,6 h of electrolysis,the the copper ions in the effluent decreased to 5 g/L,the current utilization rate could be maintained at 55% to 80%.The ammonium persulfate in the waste liquid was increased to about 120 g/L under different electrolysis conditions.The optimum conditions were determined by measuring the concentration of ammonium persulfate and comparing the current utilization rate during electrolysis.The optimal conditions: temperature at low temperature(17 °C),ammonium sulfate dosage was 140 g/L,KSCN dosage was 1.6 g/L,the dosage of copper ion concentration was 5 g/L,the volume fraction of sulfuric acid was 3%,the current density was 300 m A/cm2,a cationic membrane Nafion117,electrolytic concentration 7 h.Ammonium persulfate could be increased to about 120 g/L,the current utilization rate could be maintained at 50% to 75%.Cyclic regeneration and etching in the cathode electrolysis under the optimum conditions of removal of copper copper ion would be reduced to 5 g/L,then the optimal conditions of membrane electrolysis anode electrolytic synthesis of ammonium persulfate under the ammonium persulfate concentration increased to about 120 g/L,electrolytic anode,current utilization ra te could be respectively maintained at 55% to 90% and 40% to 70%,and then used for etching copper etching effect by measuring the etch rate to evaluate the regeneration of etching solution,after etching can be observed after copper surface becomes rough,but with the increase of the cycle,the regeneration effect w ould become worse.Synchronous regeneration and etching,the diaphragm separates the cathode and anode,the optimum conditions in cathode electrolysis and membrane electrolysis to remove copper anode for electrolytic synthesis of ammonium persulfate,the Yin and Yang pole synchronous use synchronous removal of cathode electrolysis copper current utilization rate than the different step,and When the anodic in situ ammonium sulfate was produced by the membrane electrolysis method,the current utilization ratio was not quite different when the anode was not synchronized. |
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