Interest of micro-reactors for the implementation of advanced electrocatalytic oxidation with boron-doped diamond anode for wastewater treatment

Abstract Boron-doped diamond (BDD) anode has attracted great attention in the last two decades for its surpassing performance in advanced electro-oxidation treatment of wastewater and disinfection. Due to the heterogeneous-like oxidation of organic pollutants, more suitable electrochemical reactor designs have been more recently proposed for optimal degradation and mineralization with BDD anode. Microfluidic reactors have emerged as promising alternative, by implementing submillimetric interelectrode gap in flow-by or flow-through parallel-plate system. Micro-reactors allow intensifying the mass transport of species towards the electrode, while reducing the energy consumption and avoiding the addition of supporting electrolyte. The principle and main influencing operating parameters have been discussed in this review. Perspectives of reactive electro-mixing reactor could permit to combine micro-with macro -reactors by increasing the treatment capacity while limiting the clogging effect. Further researches are required to overcome the drawbacks of micro-reactors and to benefit from electro-precipitation phenomena for the recovery of value-added compounds.