Photoelectrocatalytic oxidation of metal-EDTA and recovery of metals by electrodeposition with a rotating cathode

Publication date: 15 September 2017
Source:Chemical Engineering Journal, Volume 324
Author(s): Yutong Chen, Xu Zhao, Wei Guan, Di Cao, Tao Guo, Xiufang Zhang, Yan Wang
In this work, a photoelectrocatalytic reactor with a rotating cathode was designed for the destruction of metal complexes and recovery of liberated metal ions. The effects of rotating speed, current density, initial pH and initial Cu-EDTA concentration on the recovery of Cu and destruction of Cu complexes were investigated. At cathode rotation speed of 100rpm, initial pH of 3.18 and current density of 0.5mA/cm², the recovery percentage of Cu and destruction of the Cu complexes were increased to be 75.54% and 74.18% from 38.98% and 37.92% at 0rpm rotation speed within 120min, respectively. Furthermore, the destruction of Co-EDTA, Ni-EDTA and Zn-EDTA complexes using the rotating cathode were investigated. The Co²⁺, Ni²⁺ and Zn²⁺ recovery percentage was increased by 29%, 19% and 18% with the optimal speed of cathode, respectively. The recovered product from the cathodic electroreduction was all crystallized. The treatment performance of the reactor for the first 5 cycles had a slight downward trend, and then the capability of the reactor tended to be stable. The photoelectroctalytic reactor with the rotating cathode exhibited the high efficiency for the recovery of liberated metal ions and destruction of metal-EDTA complexes.

Graphical abstract

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