Removal of copper ions present in waste offset printing developer by electrocoagulation-electroflotation process

Abstract

The offset printing processes produce large amounts of waste liquids (printing developers, fountain solution, cleaning solvents and inks) which can be damaging for the environment if not monitored in the appropriate manner. The application of electrocoagulation-electroflotation process helps monitor the concentration levels of copper ions in waste offset printing developer. Purpose of this study was to investigate the effects of current density on removal of copper ions from a waste offset printing developer in the batch electrocoagulation–electroflotation process. The electrochemical process was investigated at current densities of 2, 4 and 8 mA/cm2 (corresponding to 0.08, 0.16 and 0.32 A, respectively) for the contact time of 1, 5, 10, 20, 40, and 60 minutes, respectively. The results show that, for a given time, the removal efficiency of copper ions increases significantly with the increase of current density. The current density of 2 mA/cm2 produces the slowest treatment with 90.18% of copper ions reduction which occurs after only 20 minutes. The removal efficiency of copper ions at a current density of 4 mA/cm2 was 92.44% after 10 minutes. The kinetics of electrocoagulation–electroflotation process at a current density of 8 mA/cm2 is very fast (5 minutes), and the removal rate reached 92.02%. The electrocoagulation–electroflotation process was successfully applied to the purification treatment of waste offset printing developer where an effective reduction of copper ions concentration under prescribed limits was obtained. The conclusion has been drawn that the electrocoagulation–electroflotation process has a future as a printing effluents treatment technology.