Co-electrodeposition/Removal Of Copper And Nickel In A Spouted Electrochemical Reactor

Results are presented with single factor experiments by the co-electrodeposition of copper and nickel from acidic solution mixtures in the spouted electrochemical reactor.The effect of the electrolyte pH value,current,temperature,and sparing nitrogen on the metal removal rate,dissolved oxygen concentration,the solution conductivity,the voltage change of power supply,and deposited metal from the surface of the cathode particles were examined under galvanostatic operation.The quantitative and qualitative behavior of co-electrodeposition of the two metals from their mixtures differs significantly from that of the individual single-metal solutions.The varying conditions of the electrochemical reaction rate,the corrosion rate of the deposited metals,the displacement reaction rate,the mass transfer process are primarily attributed to the single factor change.Finally,a numerical model idea of co-electrodeposition in the spouted electrochemical reactor is presented that describes the behavior of the experimental copper and nickel ion concentrate data quiet well.During the co-electrodeposition of copper and nickel,the removal rate of Cu2+decreases with increasing the electrolyte pH value,and the removal rate of Ni2+increases with increasing the electrolyte pH value.At the beginning of the co-electrodeposition,because of displacement reaction and corrosion of nickel,the removal rate of Ni2+ is not obvious.Because anode for electrolysis of water generates oxygen,dissolved oxygen concentration increases rapidly at the beginning of the co-electrodeposition.And dissolved oxygen concentration increases with increasing the electrolyte pH value.As shown,the metal corrosion rate increases with the mass of metal increasing.The removal rate of Cu2+ and Ni2+ increases with increasing the current I value.Especially,changing the pH value after 210 min of co-electrodeposition,the removal rate of Ni2+ is obvious.Because of increasing current I,anode for electrolysis of water generated oxygen violently,and dissolved oxygen concentration increases with increasing current.The removal rate of Cu2+ and Ni2+ decrease with increasing temperature T,because the growth of metal corrosion rate is larger.Under the condition of different temperature,all of the dissolved oxygen concentration decrease with time which proves that metal corrosion rate increases with the mass of metal increasing.The sparing nitrogen in waste water can significantly reduce the DO concentration and reduce the metal corrosion rate,then promote the electrodeposition of copper and nickel ions.As shown,the best conditions for co-electrodeposition of copper and nickel ions at present is that the cathode particles is 1.8mm,1=15A,T=25?,pH=3.0 from 0 to 210min and pH=4.5 from 210 to 480min,and sparing nitrogen.after electrodeposition of 360 min,the concentration of Cu2+in electrolyte is less than 5 mg/L,and finally Ni2+ in the electrolyte concentration is 147.9 mg/L.And under this condition,the average current efficiency of electrodeposition for copper is 62.64%,and within 330 min of electrodeposit,current efficiency is greater than 50%.The metal plating of copper and nickel bead on the surface of copper particles cathode is bright and high-density.The metal plating of copper and nickel bead on surface of copper particles cathode which is observed by SEM is gradually with time,and copper deposits is higher-density than nickel deposit.Both two metals deposit in a row,but the shapes of copper and nickel electrodeposition particle are different slightly.The factors of co-electrodeposition of copper and nickel in the spouted electrochemical reactor are formulated.And it is formulated the function relation between the concentration of copper and nickel ion and time in the process of electrodeposition,it is proved that the constant of corrosion rate of copper is much less than the sum of the constant of electrochemical reaction rate and the constant of displacement reaction rate to promote the electrodeposition of copper.And it is also proved that the constant of corrosion rate of nickel is much less than the difference of the constant of electrochemical reaction rate and the constant of displacement reaction rate to promote the electrodeposition of nickel.And it is compared that the electrodeposition conditions of nickel is more difficult to copper,and which is consistent with the experiment conclusion.After current closed,the formulas of Cu2+ and Ni2+ concentration wtih time are also formulated owing to the corrosion of deposited metals and metal displacement reaction,which is compared with the approximation curve of experimental values simulated by the five order polynomial,and that is consistent to the conclusion.