The Treatment Of Electoplating Nickel-Containing Wastewater With Combined Process Of The Ferrite And Carbonite

The nickel electroplating wastewater can be serious harm to the people and environment because of its complexity, high concentration and toxicity, so it cannot be discharged unless the pollutants are controlled under standards.The high concentration of nickel electroplating wastewater which is about 4000mg/L that come from a electronics factory in Qingdao, Shandong province cannot be discharged standard by the treatment of iron powder replacement or the combined process of chemical precipitation-reverse osmosis-ion exchange method. According to enterprises requirement, the treatment of nickel electroplating wastewater with combined process of the ferrite and CARBONITE has been made on this paper, the best conditions are discussed in order to reach the discharge standards.Firstly, the nickel electroplating wastewater was treated by the ferrite process, the influencing degree of primary factor such as pH value, n(Fe²⁺):n(Fe³⁺), m(FeSO₄·7H₂O):m(Ni²⁺), reaction temperature and reaction time on the Ni²⁺ removal rate were discussed by the orthogonal experiment, and then the best conditions were determined through the single factor experiment. The results of orthogonal experiment showed that pH value was the main influencing factor, and the others influenced comparatively less. The results of single factor experiment showed that the concentration of Ni²⁺ was reduced to 6.8mg/L from 4212.5 mg/L, the removal rate was 99.84% when pH value was 11.0, m(FeSO₄·7H₂O):m(Ni²⁺) was 21, n(Fe²⁺):n(Fe³⁺) was 0.55, reaction temperature and reaction time were 30℃and 15min respectively, The ferrite process was effective to treat wastewater and the treated effluent water meat the need of follow-up treatment.After the ferrite process treatment, the nickel electroplating wastewater was treated by CARBONITE. Some influencing factors of the nickel ions removal were investigated, such as dosage of CARBONITE, pH value, temperature, and reaction time, at the same time investigated the subjects of CARBONITE of regeneration. The results showed that when the dosage of CARBONITE was 1.5g/L, pH value was 6.5, the temperature was 35℃and the reaction time was 6h, the removal rate of Ni²⁺ can reach to 96.48%, the concentration of Ni²⁺ decreased to 0.5mg/L, reached the primary discharge standards. The removal rate of Ni²⁺ could still reach to about 83.11% when using the regenerative CARBONITE three times.According to the economic feasibility analysis, it is feasible to adop combined process of the ferrite and CARBONITE, because it only cost 597.82yuan/ton, but now the enterprise should cost 700yuan/ton to treat wasterwater, or it will cost 1600yuan/ton to send the water to the other enterprise.