Model Unraveling the Ultra-Efficient Multi-Stage Flow-Through Anodes for Water Purification Application: Development of Design and Evaluation

Abstract

Improving energy utilization efficiency is crucial to broadening the prospects in the field of electrochemical wastewater treatment. The electrochemical flow-through (FT) mode shows the potential prospect of high oxidation efficiency and low energy cost. In this study, based on the SnO2-Sb2O3 macroporous anode, we designed a multi-stage flow-through (MSFT) anode that significantly enhanced the organic removal performance than that of a conventional FT system. Accordingly, we first proposed the current reaction kinetics model that could appropriately describe the removal performance in the MSFT electrochemical oxidation process. The mass transfer impact of MSFT was also suitably evaluated by our model, which indicated that the MSFT could rapidly achieve the same diffusion flux for electrochemical oxidation limitations. The energy consumption per order of magnitude removal (EE/O) was below 0.12 kWh m–3 for low-concentration organics, which sharply decreased with an increase in the flow. For the simulation of low conductivity of water quality (∼439 μS cm–1), we found that the MSFT could obtain the voltage reduction of approximately 25% for saving energy without the extra electrolyte. Finally, we summarized the nominalized electron utilization performance of organic destruction on various electrochemical advanced oxidation anodes. The normalized removal rate of contaminants per current was greatly improved by the MSFT mode and our highly efficient anode. Notably, the MS design can prolong the anode usage lifetime. We anticipate that our work will provide design development for other anodic interfaces in the field of electrochemical wastewater purification applications.