Additive manufacturing or 3D printing has made possible considerable advancements of various technologies in many fields of engineering. However, the benefits of 3D printing for electrochemical wastewater treatment in two different applications have only recently been considered. Here we disclosed two distinct applications related to the (photo)electrocatalytic technology. First, a 3D-printed PTFE carbon cloth gas diffusion electrode (PTFE-CC-GDE) was coated for the first time with electrochemically exfoliated graphene in order to improve the generation of H2O2 and thus the mineralization of real industrial electronics wastewater by electro-Fenton (Fig. 1). Remarkably, the graphene-coated GDE allowed reaching H2O2 concentrations as high as 495 mg L-1 (specific H2O2 production of 28 mg cm-2). As a result, over 80% of mineralization of electronics wastewater was achieved following 180 min of EF under the optimum operating conditions (29 mA cm-2, 0.2 mM of Fe2+ and 0.2 L min-1 air flow). Then, a novel 3D-printed flow-cell reactor was designed to maximize the distance of electrode separation and the contact between gaseous O2 and the carbon cathode for photo-electrocatalytic treatment of phenol (Fig. 2). With this design, UVA irradiation shining through a fluorine-doped tin oxide (FTO )anode – with a transmissivity of 65% – improved the kinetics of photolytic reactions as compared to dark processes, with a synergy value (SUV) as high as 1.87. Thanks to these enhancements, the global phenol degradation rates could further increase to 0.0175 min-1, 14% higher than within a stirred glass reactor (0.0153 min-1). Following optimization of the current density and Fe2+ concentration, the kinetic rate of degradation attained 0.0214 min-1, an all-time high showcasing the promises of the novel 3D-printed reactor.

Innovative 3D printed materials for electrochemical wastewater treatment

2019 Spring National Meeting

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