Anodic oxidation of esomeprazole in water by carbon coated titanium (C/Ti) electrode: Optimization and degradation analysis

Abstract

Esomeprazole (ESO) is one of the proton pump inhibitors (PPIs) that is commonly used to treat extreme acidity and gastrointestinal irritation. Since it is used at a high rate, it is now classified as a pollutant of emerging concern (CEC). ESO gravely jeopardizes the health of living beings because it persists in water and wastewater sources even after standard treatment. Studies on the effective removal of PPIs, especially ESO, are scarce. In the current study, esomeprazole is disintegrated in water using electrochemical oxidation (EO). Titanium cathode with sodium sulfate electrolyte and carbon coated titanium (C/Ti) anode were used to apply EO. Through optimization studies utilizing COD measurement, it was discovered that 93% of the COD could be removed at pH 3, 60 mM sodium sulfate concentration, 300 min treatment period, and 115 mA cm−2 current density. Whereas TOC research revealed only 44% mineralization, HPLC‐PDA experiments revealed 100% ESO transformation. High resolution mass spectrometry (HRMS) studies were used to propose a degradation mechanism and pathway. The primary processes of degradation included desulfurization, thioperoxole group formation, sulfinyl benzimidazole group breakage, and demethylation. More than 20 reuses of the anode and cathode materials were possible without significantly lowering their oxidation efficiency.