Application of electrodialysis enhanced with complex formation integrated with electrolysis for treatment of electroplating wastewaters as a new approach to the selective copper recovery

Abstract

The electroplating industry produces a large amount of wastewaters containing economically important metals, such as copper. Usually, the copper electroplating wastewaters are diluted and contaminated with ferric ions. Therefore, selective copper resource recovery from wastewater should be a crucial strategy to mitigate environmental change. This paper focuses on gaining new insights into the electrochemical treatment of copper postgalvanic wastewater contaminated with ferric ions and, as a consequence, selective copper preconcentration and finally copper recovery in metallic form. To achieved this goal the integrated method of electrodialysis (ED) enhanced with disodium ethylenediaminetetraacetate (Na2EDTA) as a complexing agent and the electrolysis (EL) was applied. What is limited by using simple ED or EL methods. It was found that, in ED enhanced with complex formation, the Na2EDTA allowed for the selective bonding of ferric ions. The influence of ferric salt concentration and ED parameters on ED performance was evaluated in terms of selectivity rate factor, ferric ion retention, copper(II) recovery and concentration degree. Furthermore, copper recovery from concentrate after ED by EL was examined. It was concluded that the ED enhanced with a Na2EDTA as the complexing agent promoted 92.2% copper(II) recovery with a 2.95-fold increase of copper(II) in the concentrate and with a ferric retention coefficient of 94.3%. Moreover, the EL of concentrate after ED allowed for the effective recovery of copper on the surface of the cathode. Almost 94.49% of copper was recovered with purity of 99.4%. Therefore, the application of ED enhanced with complexation and EL methods can improved selective copper recovery from wastewater contaminated with ferric ions.