Simultaneous dehalogenation and oxidation of dichloroacetamide by Cu-modified CoFe-LDH in three-dimensional continuous flow aerated electrocatalytic reactor

• 3D CFAER system is built for by products DCAcAm abatement in disinfected water. • The design of synchronous redox process is applied in this work. • The role of Cu modification of LDHs on the performance of water treatment is discussed. • The mechanism is proposed via characterization techniques and DFT calculation. • 3D CFAER system with Cu modified LDHs can be applied to the actual wastewater treatment . Searching for catalysts and degradation systems for synchronous dehalogenation and oxidation of haloacetamides (HAcAms) is pressing. In this study, a novel three-dimensional continuous flow aerated electrocatalytic reactor (3D CFAER) system, which employed Cu-modified CoFe layered double hydroxides (CoFe-LDH) composite/activated carbon as a catalytic particle electrode for the degradation of dichloroacetamide (DCAcAm) was constructed. Under the experiment’s optimal operating parameters, the maximum degradation rate of DCAcAm reached 91.7 %. The superior performance for the degradation of DCAcAm was due to the enhanced electron transfer induced by the modification of Cu in CoFe-LDH. Moreover, Density Functional Theory (DFT) calculations indicated that Cu doping improved the ability of LDH to dissociate water, thereby enhancing its electrocatalytic performance. Scavenger experiments and Electron Paramagnetic Resonance (EPR) results revealed that •OH, O 2 •– and electrochemical direct dehalogenation were responsible for DCAcAm removal. Additionally, the electrocatalytic stability of the electrode was tested upon repeated use with DCAcAm degradation remaining as high as 81.7 % after five consecutive experiments. More importantly, in 3D CFAER, electrocatalytic treatment lasting 90 min reduced the TOC and COD of the actual chlorine disinfection wastewater by 64.1 % and 74.9 %, respectively. This study provides new theoretical basis and technical support for control of HAcAms.