Electro-oxidation of Ni(Ⅱ)-citrate complexes at BDD electrode and simultaneous recovery of metallic nickel by electrodeposition

作者：Qiongfang Zhuo; Xiaofeng Xu; Shuibo Xie^*; Xiuwen Ren; Zhongying Chen; Bo Yang; Yanliang Li; Junfeng Niu

来源：Journal of Environmental Sciences, 2022, 116(06): 103-113.

• Electrochemical oxidation
• Electrodeposition
• BDD anode
• Metal complexes
• Metallic nickel recovery

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 p H, 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 m A/cm2, p H 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 k Wh/L at a current density of 10 m A/cm2(p H 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.

• 单位
  东莞理工学院