Study On Treatment Of Simulated Copper-containing Wastewater By Electrodeposition And Its Crystallization Behavior

Ultrafine copper powder refers to copper powder with a particle size of less than10?m,which has excellent performances such as high activity,isotropy and strong reducibility.It is prepared in lubricating oil,catalyst,coating material,aerospace field and composite conductive material.Other aspects have high utilization value.Ultrafine copper powder was prepared from acidic Cu SO4 solution?Simulation of copper-containing wastewater?by electrochemical deposition.The copper deposited on the surface of the cathode was dispersed into the electrodeposition liquid by ultrasonication and surfactant addition.The optimum process conditions were obtained by changing the current density,Cu???concentration,ultrasonic power,H?I?and other related parameters by single factor experiment.The surface morphology of the copper powder was observed by SEM.The phase structure of the copper powder was analyzed by XRD,and the particle size of the copper powder was detected by a particle size analyzer.The mechanism of the influence of surfactant polyvinylpyrrolidone?PVP?on the electrocrystallization process of copper was studied.In the Cu SO4-H₂SO₄ system,the linear sweep voltammetry curve?LSV curve?of copper electrocrystallization process and the It curve and AC impedance spectrum?EIS?at different step potentials were measured by Autolab electrochemical workstation.The change determines the reduction mechanism and nucleation history of Cu???electrocrystallization process,and calculates the relevant nucleation kinetic parameters.After the AC impedance curve is simulated,the equivalent circuit is used to replace the solution reaction process,and the data of each component is analyzed.the result shows:?1?When the ultrasonic power is 200 W,the current density is 6 A/dm2,the concentration of Cu???is 0.04 mol/L,and the concentration of H?I?is 0.25 mol/L.The purity of copper powder reached 99.08%,and the copper powder obtained was well dispersed and the particle size of the copper powder was small.?2?Infrared spectroscopy has detected that the C=O bond participates in the complexation reaction of Cu???to form a complex compound of PVP-Cu,which shows that the absorption peak of the C=O bond is shifted.The linear scanning voltammetry curve and cyclic voltammetry curve show that after adding 2 g / L PVP,the cathodic polarization is increased.As the PVP concentration increases,the stronger the polarization effect,the greater the negative shift of the deposition potential;The complexation of PVP and Cu???synthesis inhibits the reduction of Cu???and increases the cathodic polarization?3?In the chrono-current curve,as the step potential is more negative,the peak currents of Cu and Cu/PVP gradually increase,the nucleation relaxation time is shortened,and the nucleation rate is increased.After adding PVP to the electrolyte,thetransition from progressive nucleation to transient nucleation increases with the increase of concentration.By nonlinear fitting the I-t curve,the results of calculating the kinetic parameters show that at 2 g/L,the number of nucleation sites increases and the rate of nucleation increases.?4?The AC impedance test shows that the Nyquist spectra of the electrolyte solution without PVP and PVP are composed of a high-frequency capacitive reactance arc and a low-frequency straight line.The data of each circuit element in the ZView fitted circuit diagram shows that PVP inhibits the copper reduction process.The fitted calculation results show that it has no significant effect on the electrode/solution interface electric double layer,which mainly changes the diffusion resistance and Faraday resistance of the copper electrodeposition process.