3D-printed electrochemical systems: A dual approach for H2O2 production and antibiotic degradation

The growing demand for hydrogen peroxide (H 2 O 2 ) is driven by the development of advanced wastewater treatments targeting emerging pollutants. One of the most sustainable methods to produce H 2 O 2 is via the electroreduction of O 2 . Herein, we propose the use of fused deposition modelling (FDM) 3D printing for the fabrication of cathodes for this reaction. Cathodes were composed of polylactic acid (PLA) and two different carbon materials, carbon black (CB) or polypyrrole (PPY). PPY and CB catalysts were characterized by Raman spectroscopy both as powders and as part of the 3D-printed electrodes. A reduction process was optimized to activate the 3D-printed electrodes. These electrodes demonstrated H 2 O 2 production at circumneutral pH (pH 0 = 5) and low current densities, with the activated PPY:50 electrode exhibiting the best performance, operating at –0.5 mA cm −2 with a Faradaic efficiency of 47 % and a production of 0.78 mM after 1 h. The stability of the produced H 2 O 2 was studied, demonstrating its feasibility for storage at low temperatures for subsequent use in wastewater treatment. The target antibiotic, ofloxacin (OFX), was treated with the produced H 2 O 2 , generating ● OH radicals through a 3D-printed catalyst composed by zero valent iron (ZVI) microparticles and PLA. Both ex-situ and in-situ degradation methods were effective, including treatments in real wastewater effluent. This work highlights the potential of 3D printing technology to create customizable and low-cost electrodes for advanced wastewater treatment. • 3D printing enables the fabrication of sustainable cathodes for H 2 O 2 production. • 30 days stored H 2 O 2 is later used to effectively depollute wastewater pollutants. • 3D printed supported catalysts successfully degrade ofloxacin. • Hydrogen peroxide is electrogenerated and degraded simultaneously for purification.