TY - JOUR ID - 10.1016/j.jes.2021.05.034 TI - Electro-oxidation of Ni (II)-citrate complexes at BDD electrode and simultaneous recovery of metallic nickel by electrodeposition AU - Qiongfang Zhuo AU - Xiaofeng Xu AU - Shuibo Xie AU - Xiuwen Ren AU - Zhongying Chen AU - Bo Yang AU - Yanliang Li AU - Junfeng Niu VL - 34 IS - 6 PB - SP - 103 EP - 113 PY - JF - Journal of Environmental Sciences JA - J. Environ. Sci. UR - http://www.jesc.ac.cn/jesc_en/ch/reader/view_abstract.aspx?file_no=S1001074221002126&flag=1 KW - Corresponding author.;Electrochemical oxidation;Electrodeposition;BDD anode;Metal complexes;Metallic nickel recovery AB - The simultaneous electro-oxidation of Ni (II)-citrate and electrodeposition recovery of nickel metal were attempted in a combined electro-oxidation-electrodeposition reactor with a boron-doped diamond (BDD) anode and a polished titanium cathode. Effects of initial nickel citrate concentration, current density, initial pH, electrode spacing, electrolyte type, and initial electrolyte dosage on electrochemical performance were examined. The efficiencies of Ni (II)-citrate removal and nickel metal recovery were determined to be 100% and over 72%, respectively, under the optimized conditions (10 mA/cm2, pH 4.09, 80 mmol/L Na2SO4, initial Ni (II)-citrate concentration of 75 mg/L, electrode spacing of 1 cm, and 180 min of electrolysis). Energy consumption increased with increased current density, and the energy consumption was 0.032 kWh/L at a current density of 10 mA/cm2 (pH 6.58). The deposits at the cathode were characterized by scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). These characterization results indicated that the purity of metallic nickel in cathodic deposition was over 95%. The electrochemical system exhibited a prospective approach to oxidize metal complexes and recover metallic nickel. ER -