Nickel recovery from electroplating sludge via bipolar membrane electrodialysis

In this study, nickel (Ni) was recovered from electroplating sludge in the form of Ni(OH)(2) using a bipolar membrane electrodialysis (BMED) system. The results showed that the H+ generated by the bipolar mem-brane could effectively desorb Ni from the sludge to the solution and the solution pH considerably affected Ni desorption. The desorption process can be described using the first-order kinetic model. The current density and solid/liquid ratio (m/v) considerably affected Ni recovery. Moreover, 100% of Ni was removed from the electroplating sludge and 93.5% of Ni was recovered after 28 h under a current density of 20 mA/cm(2), a solid/liquid ratio of 1.0:15 and an electroplating-sludge particle size of 100 mesh. As the number of electroplating compartments increased from one to two and three, the current effi-ciency for recovering Ni changed from 12.1% to 11.8% and 11.9%, respectively, and the specific energy consumption decreased from 0.064 to 0.048 and 0.039 kW center dot h/g, respectively. Fourier-transform infrared spectroscopy and Raman spectroscopy showed that the precipitate obtained in this study is similar to commercial Ni(OH)(2) and the purity of Ni(OH)(2) in the obtained precipitate was 79%. Thus, the results showed that the BMED system is effective for recovering Ni from electroplating sludge.(c) 2023 Elsevier Inc. All rights reserved.