Electroplating wastewater often contains such complex agents as EDTA and some heavy metals exist in complexing form

which present great challenge for heavy metal removal. Given the low cost and satisfying effect of microelectrolytic method in processing complex wastewater

iron-copper microelectrolysis was adopted to treat the EDTA complex copper solution. Analysis of the change of metal ions and the infrared spectrum of the precipitates during microelectrolysis showed that the major changes occurred were iron dissolution

increased concentration of Fe2+ and Fe3+

decreased Cu2+ concentration

accompanied by a slight decrease in EDTA concentration and the formation of Fe(OH)3 precipitate. MINTEQ software was used to simulate the complex morphological distribution. The results show that the addition of Fe3+ can make Cu2+ into a free state. The larger the Fe3+/Cu2+ is

the lower the pH is

hence the better the removal effect. The addition of Fe2+ under alkaline conditions can make Cu2+ become Cu(OH)2. The greater the Fe2+/Cu2+ is

the higher the pH is

the better the removal effect. Combining with the experimental and simulation results

it can be concluded that the desorption of Fe3+ under acidic conditions and the reduction of free Cu2+ by iron scrap are the main reasons for the removal of Cu2+-EDTA by microelectrolysis.