Testing and scaling-up of a novel Ti/Ru0.7Ti0.3O2 mesh anode in a microfluidic flow-through reactor

Abstract This work investigates the scale-up of the electrolysis and photo-electrolysis of water polluted with clopyralid using a novel Ti/Ru0.3Ti0.7O2 mesh anode produced by CO2 laser. Two different cells were used: a mixed tank cell (MT) and a microfluidic flow-through reactor (MF-FT). The main advantages of the MF-FT reactor are the simultaneous reduction of the ohmic resistance and mass transfer limitations, which are two critical factors in electrochemical oxidation. Thus, the goal is the scale-up evaluation and the study of the effects of the kind of water matrix towards practical application of the laser-made anode in water treatment. Aqueous solutions of clopyralid and groundwater intensified with this pollutant were studied in the context of the scale-up evaluation to clarify the effects of the water matrix. Single photolysis was also studied for comparison purposes. It was demonstrated that photo-electrolysis results in a faster clopyralid and TOC removal in both the MF-FT reactor and mixed tank cells as compared to single electrolysis. This work also focuses on the synergy coefficient to evaluate the effect of the coupling of different processes on system performance. Higher synergistic effects occur on clopyralid removal in the MF-FT reactor (110% and 358%, for natural groundwater and synthetic water, respectively) and TOC (233.3% and 15396% for natural groundwater and synthetic water, respectively). The best performance was obtained in the MF-FT reactor, which was attributed to the more uniform potential/current distribution associated with the reduced interelectrode gap (few microns) in comparison with the MT cell (gap of one centimeter), which also results in reduced energy consumption.