Recovery of nickel and water from nickel electroplating wastewater by electrodialysis

摘要

Galvanic processes are one of the main activities contributing to metal discharges into the environment. The wastewater generated contains a high load of salts and metals that should be treated. In this work, the electrodialysis (ED) treatment was studied in order to concentrate and extract nickel (Ni) and its salts of effluents from the bright nickel electroplating process, aiming at water and concentrated solution recovery for reuse, and saving industrial and environmental resources. A laboratory-scale ED system was applied in the treatment of a synthetic effluent based on industrial bath composition. Properties of recovered water and nickel-concentrated solution have also been analyzed to verify their quality: Both solutions were used in the nickel-plating process in order to analyze their effects on the properties of electroplated pieces. It was found that ED treatment generates a very low conductivity solution, enabling its reuse as rinsewater, and a concentrated solution, which can be fed to the bath to recover volumes lost by evaporation and drag out during the nickel-electroplating process. The reuse does not cause any harm to the quality of plated pieces with regard to the visual aspects and corrosion resistance.