Nickel removal from wastewater by induced co-deposition using tungsten to formation of metallic alloys

Abstract

In this work, nickel was removed from industrial effluent by an electrodeposition process and the alloy obtained with this metal was characterized. The removal tests occurred in optimized conditions, under those occurred the formation of Ni-W alloy from synthetic baths prepared in laboratory. Thus, an experimental planning was performed in order to investigate the variation of nickel concentration in the bath, temperature and density of the current applied. The variable of response considered was the faradic efficiency. The metallic alloy obtained through the nickel removal of an electroplating wastewater was characterized by X-ray Diffraction, Infrared Spectroscopy and Scanning Electron Microscope with chemical analysis by Dispersive Energy of X-rays. The faradic efficiency was strongly influenced by the nickel concentration, achieving a value of 51.4%. In the test of nickel removal from a real wastewater, the faradic efficiency registered was approximately 90% and the nickel removal was 38.76%. The coating obtained from the real wastewater was characterized by a high level of crystallinity and pureness. The Scanning Electron Microscope images showed that the metallic alloy of Ni-W was cracked, which may be related to its crystallinity. Ni and W contents in the alloy were approximately of 73 and 27%, respectively.