Water pollution due to the presence of hazardous contaminants of emerging concern is a major environmental issue that has mobilized water scientists and engineers across the globe. Electrochemical advanced oxidation processes (EAOPs) for wastewater treatment have been in the spotlight in recent years because of their high efficiencies, ease of operation and environmental compatibility. Among them, photoelectrocatalytic methods have emerged as potent tools combining the benefits of electrochemistry and photocatalysis to degrade a variety of contaminants 1. In the present work, a TiO2-coated fluorine-doped tin oxide (FTO) transparent photoanode (FTO-TiO2) was synthesized by spin coating and applied to the photoelectrocatalytic (PEC) degradation of the persistent fungicide triphenyltin chloride (TPT). The efficiency of the FTO-TiO2 photoanode and its photoelectrocatalytic properties were firstly evaluated for the degradation of phenol as model pollutant, which allowed determining the optimal working potential (2.5 V for 76.1% of TOC removal in 6 h). Then, the PEC process was coupled to photoelectron-Fenton (PEF) by the utilization of a carbon-felt cathode that promoted the production of H2O2 by the 2-e- reduction of dissolved O2. In this way, homogeneous generation of OH radicals via the Fenton’s reaction paired to the photoelectrocatalytic oxidation at the anode enhanced TPT degradation and mineralization yields, achieving total removal in only 10 min of electrolysis (kapp = 0.7786 min-1) and complete mineralization to CO2 following 2 h. As comparison, 47% of TPT removal was obtained in 10 min by PEC using a Pt cathode (kapp = 0.0526 min-1), while the TOC was depleted only by 22% after 2 h (Fig. 1). These results demonstrate the potential of this combined photoelectrocatalytic process to mineralize hazardous pollutants in short treatment times.

FTO-TiO2 photoelectrocatalytic degradation of triphenyltin chloride coupled to photoelectro-fenton

2019 Spring National Meeting

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