Continuous-flow electrochemical strategy for efficient hydrodechlorination of chlorinated wastewater without cathodic...

The electrochemical dechlorination of low-conductivity chlorinated wastewater typically requires the addition of electrolytes to reduce the solution resistance. However, this approach not only increases costs but may also result in electrolyte contamination. On the other hand, the electrolyte-free alternative strategies based on membrane electrode-separated chambers generally suffer from the problems of complex electrode synthesis and device configuration as well as fragile membrane electrodes. To address these issues, this study proposes a novel continuous-flow electrochemical strategy without cathodic supporting electrolyte via utilizing commercially available and reliable membranes, which achieved efficient hydrodechlorination of chlorinated wastewater. Here, 4-chlorophenol (4-CP) acted as the target contaminant, the monodisperse palladium (Pd) nanoparticles loaded on carbon nanotubes (CNT) were used as catalysts, and the working electrode was prepared by depositing the Pd/CNT catalysts onto a carbon paper (CP) or carbon felt (CF). The feasibility of this strategy was first validated using a batch reactor, followed by the design of a continuous-flow reactor based on experimental results. After a series of parameter optimization, the continuous-flow reactor with a Pd/CNT@CF cathode achieved a high 4-CP removal efficiency (100%) and low energy consumption (25.6 kWh kg^-1), demonstrating excellent hydrodechlorination performance and operational stability. This work presents a promising catholyte-free electrochemical strategy with simple device assembly and stable electrode materials, exhibiting potential for environmental remediation applications.