Electro-oxidation of a commercial herbicide using a three-dimensional layered Ti4o7 porous anode

LUCILA DOUMIC; HERNAN ROMEO; MARIA FLORENCIA SILVA BARNI; MARIA ALEJANDRA AYUDE; RAUL PROCACCINI

Santa Fe

Congreso; X Congreso Argentino de Ingeniería Química (X CAIQ); 2019

AAIQ

This study reports the use of porous Ti4O7 electrodes for the degradation of the herbicide bentazon by electro-oxidation (EO) under both traditional batch (TB) and batch recycle flow-through modes (BRFT). Layered Ti4O7 electrodes were obtained by directional freezing of TiO2 aqueous dispersions. Different processing conditions were used in order to produce porous monoliths with a variety of interlayer distances. EO experiments showed that the removal of bentazon in the TB mode was similar for electrodes with different interlayer spaces (31% and 12% of bentazon degradation and mineralization, respectively), suggesting that differences in electrode interlayer spacing have no effect on bentazon removal, possible due to mass transport limitations. Considerably higher removal level of bentazon was obtained under the BRFT mode compared to the TB experiment. In the BRFT mode, an optimum electrode interlayer spacing was identified. Under best conditions, 85% and 47% of bentazon degradation and TOC consumption, respectively, were attained. This work demonstrates that the use of 3D layered Ti4O7 anodes under a flow-through mode is a promising approach for the enhanced EO of organic pollutants. Our results also reveal that the regulation of the electrode interlayer spacing is fundamental to increase the EO efficiency, providing a readily accessible porous structure to facilitate the liquid flow through the electrode architecture while minimizing simultaneously the pressure drop.