A review of strategies for mass transport intensification in electrochemical advanced oxidation processes for water treatment

Electrochemical advanced oxidation processes (EAOPs) represent a promising technology for the degradation of refractory pollutants in water, such as contaminants of emerging concern. These processes produce highly reactive species such as hydroxyl radicals (•OH), which are effective in oxidizing persistent organic contaminants. However, the efficiency of EAOPs is strongly influenced by mass transport phenomena, which govern the movement of species to the electrode′s surface. This review presents strategies for mass transport intensification in electrochemical reactors configurations, including flow-by and flow-through designs, as well as systems incorporating turbulence promoters, volumetric electrodes, and jet aerators. Based on experimental approaches, mass transfer coefficients (km) and dimensionless correlations (Sherwood, Reynolds, and Schmidt numbers) are evaluated to optimize reactor performance. It is shown that increasing flow velocity, enhancing current density as well as electrode surface area, and reducing interelectrode gaps can improve km values. Additionally, novel reactor geometries such as the e−NETmix system demonstrate superior mass transfer properties, promoting laminar chaotic flow and efficient contaminant degradation. This work provides a comprehensive analysis of the hydrodynamic and geometric factors that influence mass transport in electrochemical systems, offering insights into their design, scale-up, and optimization for intensified water treatment applications.