Optimization Of Treatment Process Of Nickel-containing Wastewater In Electroplating Base And Study Of Nickel Recovery By Electrodeposition

With the widely use of nickel in electroplating industry, the large amount of nickel-contain electroplating wastewater will not only easy to cause environmental pollution, but also results in the waste of metal. The nickel-contain electroplating wastewater in Longxi electroplating base of Huizhou was researched in the paper. The pretreatment process of nickel-contain electroplating wastewater was investigated, some existing problems were found and improvements and optimizations were added to it. Some suggestions about the dispose of the concentrated solution were raised in the study. The nickel-contain wastewater was treated with electrolytic method, and cathode materials, current intensity, initial concentration of nickel ions, temperature, initial pH, stirring action and buttered solution were studied as the main parameters. The major research conclusions were listed as following:(1) Under the request of clean production, environment protection and energy conservation, sustainable development, the centralized management of electroplating base is the development tendency of electroplating industry.(2) The result of pretreatment process of nickel-contain wastewater showed that the ion-exchange resin for the treatment is effective. The ion concentration in the effluent after optimization belows the national and related provinces' emissionstandard of pollutants for electroplating(0.1mg/L). The effluent of pretreatment could be reused, which can raise the economic returns, meanwhile the environmental pollution was relieved. The equipments are easy to operate and run reliably, which could be widely-utilized in electroplating industry.(3) The result of experiment of single-factor revealed that under the condition of plate distance 20 mm, electric current 15 A, temperature 50?, the initial concentration of nickel ions 20g/L, titanium plate as the anode and stirring, the recovery can reach85%,and the corresponding current efficiency was 51.8%.(4) Initial pH, current intensity, temperature and concentration of nickel ion were used as the changed factors to conduct the orthogonal experiment. The results presented the influences of the four factors on recovery were: electric current >concentration of nickel ion>pH>temperature. The optimal parameter combination of orthogonal experiment were: plate distance 20 mm, pH 6.0, current intensity 15 A,temperature 60 ?, the initial concentration of nickel ions 20g/L, titanium plate as the anode and stirring and the corresponding recovery rate was 83.7%,current efficiency was 51.0%.(5) Comparison of the optimal parameter combination of single experiment,orthogonal experiment and the parameter combination with the highest removal rate in the orthogonal experiment was used to verify the treatment effect. It showed the higher level of concentration of nickel ion is benefit to the current efficiency, and its impact on the recovery and current efficiency wasn't apparent any more when the temperature above 50 ?. So the best temperature should match with the economyand technology.(6) The result showed that acetic acid-sodium acetate buffer solution could stop pH from declining effectively, kept it in a certain range and weaken the competition ability of H+, which was benefit to the electrolysis process and could improve the recovery and current efficiency.(7) Using electrolysis to treat the enriched nickel-containing wastewater can reduce the discharge of wastewater and recover nickel effectively. At the same time,the effluent after advanced treatments can be used as cleaning and general water,which could make the enterprise production and operation cost down. It has a significant social, environmental and economic benefit.