Selection Of Cu And Ni Leaching Conditions In Electroplating Sludge And Study On The Preparation And Electro-oxidation Properties Of PtCuNi Alloy Electrode

The electroplating sludge contains a variety of heavy metal ions,no treatment and random stacking will pollute the environment and cause the waste of resources.This paper mainly explores the selection of metal leaching conditions for Cu and Ni in calcium-based electroplating sludge.In addition,we try to skip the process of separation,purification and reformulation to the preparation of high value-added catalytic materials in the process of metal recovery,so the waste liquid is directly applied to the preparation of alloys and catalytic materials.The alloy catalyst CuNi/GC was prepared.The PtCuNi/GC alloy catalyst was prepared by chemical replacement method.The electro-oxidation performance of the alloy catalyst PtCuNi/GC for alcohol was studied.The possibility of the waste metal used as the substrate of the catalytic material was preliminarily explored.The main experiments and results were as follows:1.The traditional way is to use sulfides such as Na₂S and?NH₄?₂S as treatment agents to treat electroplating sludge,which exists some defects.First of all,S itself and other substances such as H₂S are harmful to the human body and the environment.Besides,the addition of sulfide is not conducive to the recovery of metal.Electroplating sludge sample was obtained from a Zhejiang electroplating factory.The electroplating sludge was processed by the Ca salt developed by the company.The Ca salt itself is non-toxic,which makes the electroplating sludge contain fewer impurities and be more conducive to the selection of subsequent leaching conditions and the extraction of metals.Several acid or combinations of acid were used to dissolve electroplating sludge and the weight of dissolved products was detected after drying.It was determined that the best dissolving agent was sulphuric acid.The concentration of copper and nickel ions was measured by spectrophotometry,and the factors that affected the amount of metal leached by leaching agent were explored.The optimal amount of leaching agent and the required dissolved environment for each gram of electroplating sludge were further determined.At the temperature of 30u?se,d 4mL 3M sulfuric acid to leach per gram electroplating sludge and the leaching time was 30 minutes.The metal leaching rate of Cu and Ni was about 90%,which made the copper and nickel metal could be soaked to the solvent to the maximum extent in the electroplating sludge.2.With the concentration of Cu and Ni metal ions in the leaching solution as reference,two kinds of heavy metal simulation solutions of CuSO₄ and NiSO₄ were arranged.The requirements for the preparation of CuNi/GC electrode were investigated by using the method of programmed potential step and cyclic voltammetry curve,taking the glassy carbon electrode as the basic carrier.By controlling the nucleating potential of-0.2V,the nucleation time of 1s,the growth potential of-0.15V and the growth time of 300s,the CuNi/GC alloy electrode can be prepared.The morphology of metal alloy electrodes prepared by this method was relatively uniform,and there was almost no agglomeration phenomenon.CuNi alloy was prepared by electroplating sludge leaching solution.The potential of the alloy was different from that of the simulated liquid.The nucleation potential was-0.18V,the nucleation time was 1s,the growth potential was-0.13V and the growth time was 300s.The PtCuNi/GC alloy electrode was obtained by replacement reaction in chloroplatinic acid solution with CuNi/GC alloy electrode as carrier.By controlling the replacement time,PtCuNi/GC alloy electrode with different Pt content could be obtained,and its electro-oxidation performance for alcohol was measured.By comparison,the catalytic performance of PtCuNi/GC alloy electrode prepared by electroplating leaching solution was obviously lower than that of copper sulfate and nickel sulfate solution.The catalytic performance of the alloy for 3min replacement was the best and the maximum current density was330.3mA/mgPt.When the mixed solution of copper sulfate and nickel sulfate was used as the deposition solution,the current density was 1046.4mA/mgPt.These basic explorations have established a theoretical foundation for further industrialization research,making the practical application possible.