Use of WO_2.72 Nanoparticles/Vulcan® XC72 GDE Electrocatalyst Combined with the Photoelectro-Fenton Process for the Degradation of 17α-Ethinylestradiol (EE2)

Abstract

This study proposed the use of electrochemical advanced oxidation processes (EAOPs) for the degradation of 17α-ethinylestradiol (EE2). Initially, hydrogen peroxide electrogeneration was performed using a gas diffusion electrode (GDE) cathode prepared with the electrocatalyst Vulcan® XC72 modified with WO_2.72 nanoparticles and a boron-doped diamond (BDD) anode. Subsequently, the photoelectrodegradation of 20 mg L⁻¹ EE2 was performed in a synthetic solution under the following conditions: 0.50 mmol L⁻¹ Fe²⁺, 0.10 mol L⁻¹ K₂SO₄, pH 3.0, 20 °C at different current densities (j = 150, 200, 250, or 300 mA cm⁻²). Degradation efficiency was evaluated by determining the organic matter content through total organic carbon (TOC) analyses. Finally, TOC reductions of 74.5, 88.4, 88.3, and 93.6% were obtained for synthetic EE2 solutions prepared in deionized water, reuse water, tap water, and mineral water, respectively, when performing degradation at 300 mA cm⁻². Intermediate compounds were identified using high-performance liquid chromatography (HPLC), and the predominance of oxalic acid was observed. The use of photoelectro-Fenton process joined with a cathode composed of an electrocatalyst of Vulcan® XC72 modified with WO_2.72 nanoparticles and a BDD anode were very efficient to degrade synthetic EE2 solutions in different water matrices, probing that Vulcan® XC72 modified with WO_2.72 nanoparticles is not only an excellent material for dyes degradation but also to hormones remotion.

Graphical abstract