Elimination of copper and nickel from wastewater by electrooxidation method

Abstract

Electrooxidation method was used to remove copper and nickel from water by iron sacrificial sheets in an electrolytic cell. The effect of various voltages, electrooxidation time, and the initial pH of water has been studied on removal efficiency. The concentration of heavy metals before and after treatment was determined by an AAS instrument. The sludge obtained after treatment has been characterized using XRD, FESEM, and VSM. Our results show that the operational parameters play an important role on removal process. AAS results confirmed that the concentration of heavy metal pollutants in the water effectively decreases by increasing the applied voltage, electrochemical reaction time, or the initial pH of water. Based on these results it is possible to highly decrease the concentration of Ni or Cu from water at pH ∼4.5 by applying ∼28V for 60min. The FESEM images showed the nano-size of synthesized particles during water treatment. The element maps confirmed the presence of iron, oxygen, and heavy metal pollutants in precipitate after water treatment. The XRD patterns of powder sample obtained after removal of Ni or Cu show the reflections of Fe3O4 and some small peaks which are correspond to different compound of metal pollutants. VSM results showed that the sludge samples are magnetically soft and their specific magnetization depends on removal conditions. The magnetic property of the sludge samples helps to separate them easily from water using magnetic field.