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

Boron-doped diamond (BDD) anode has attracted great attention in the last two decades for its surpassing performance in the 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 a promising alternative by implementing submillimetric interelectrode gaps in flow-by or flow-through parallel-plate systems. Micro-reactors allow intensifying the mass transport of species toward the electrode while reducing the energy consumption and avoiding the addition of supporting electrolytes. The principle and main influencing operating parameters have been discussed in this review. Perspectives of the reactive electro-mixing reactor could permit the combination of micro-reactors 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.